DEAR ABBY: My younger sister "Marni" is 15 and paranoid about her weight because when she was younger she was teased about being fat. From what I have learned on the Internet, she may suffer from anorexia.

Marni barely eats most of the time, but occasionally she'll stuff herself and then get rid of it by throwing up in the bathroom. She has also started taking laxatives. We share a room, so I see her without her clothes on, and her body is wasting away. It's not obvious when she's dressed, but when she's undressed she's literally skin and bones.

Marni says she's "fine" and will stop her behavior "once she gets her weight down," even though she's already much too thin. She won't let me say anything to Mom, who doesn't seem to realize what's going on. What should I do? I know she needs help. -- ANXIOUS IN LEXINGTON, KY.

DEAR ANXIOUS: Marni is NOT fine. You should tell your mother immediately what she has been doing because her life could depend on it. Her distorted body image is not her fault. She needs professional help and should be seen by your family physician immediately.

Throwing up after meals and taking laxatives are symptoms of a severe, life-threatening eating disorder. As you probably learned online, anorexia has the highest mortality rate of any mental illness.

Nearly 10 million women and 1 million men suffer from an eating disorder. The National Eating Disorders Association has many thousands of members and offers programs and information to support individuals, families and friends who have been affected by eating disorders. Its Information and Referral Helpline ((800) 931-2237) and Web site (� HYPERLINK "http://www.nationaleatingdisorders.org" ��www.nationaleatingdisorders.org�) offer the latest information available on recognizing the early warning signs and getting quality treatment and support.

Eating disorders are treatable if caught in time, and recovery is possible. Marni is fortunate to have a loving sister who cares about her welfare, and I'm glad you wrote.

DEAR ABBY: My daughter is 20 and finishing her second year of college. She lived in a dorm the first year and now shares an apartment in another city.

When she comes home for the weekend, do I have the right to expect her to follow a few rules while she's under my roof? She thinks she should be able to do whatever she wants since she is 20 and living independently while at college.

I think she should show us respect by abiding by her curfew (2 a.m.) and not spending the night with her boyfriend. I am tired of lying awake waiting to hear her come in so I'll know she's safe. What she does at school is different because I'm not so tuned in to her comings and goings, but when she's here, I worry.

Am I asking too much, or is she being inconsiderate? -- EXHAUSTED AND FRUSTRATED, HAMILTON, OHIO

DEAR E AND F: I think we both know the answer to that question. If your daughter were as mature as she thinks she is, she would understand that it's a parent's job to worry. She'd have more sensitivity and respect for your feelings, and be less centered on herself.

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DEAR ABBY: Our kids have decided not to have kids. Although we have no choice but to accept it, and would never express our disappointment or lay a guilt trip on them, we still have feelings about it. It's our biggest sadness.

All the people we know have grandchildren. At holidays they have toys to buy, cookies to bake, dinners to plan. Our friends and relatives tell us that because we won't have grandkids we can buy ourselves something extra-special. It doesn't make us feel any better.

An entire chapter of our lives will be missing. No one will call us "Grandma" or "Grandpa." Are our feelings legitimate, or are we whining about nothing? -- NOBODY'S GRANDMA

DEAR NOBODY'S GRANDMA: You are whining about something. However, if you feel left out because you won't be buying toys at holiday time, baking cookies and being called "Grandma" and "Grandpa," I have a suggestion for you. "Adopt" a needy family with small children and assume that role. You need only look as far as your nearest homeless shelter, program for abused women, or ask someone in Social Services to find one for you. I guarantee you'll be greeted with open arms and open hearts.

DEAR ABBY: My mother is a hardworking farm woman in her early 60s who never bothered to take care of her skin. She recently went through menopause, and now her face looks much older than her years.

Mom is a good person. Every wrinkle and laugh line has been well-earned. However, several people have made comments to her like, "What happened to you? You look terrible!"

How should Mom respond to this? I suggested she say with smile, "I'm getting old, and I look it!" She feels that would be too harsh. Do you have a more subtle answer for these insensitive people? -- PROUDLY AGING, READING, MINN.

DEAR PROUDLY AGING: There's an old saying: "It takes an enemy and a friend to hurt you to the core. The enemy to slander you, and the friend to get the 'news' to you." Your suggested response to the tactless individuals who would say such a thing to your mother isn't "harsh" -- it's right on target. If your mother tried for something more subtle, the people wouldn't get the message.

DEAR ABBY: My brother "Albert's" in-laws charge him and his new wife to attend family events. Example: When they are invited to the in-laws' lake house, they must bring $20 to cover the gas for the boat. Last Christmas they were charged $10 apiece for the family's annual shrimp boil, and $50 for a grandparent's birthday party.

The in-laws are not poor. They could well afford to host these events for their relatively small family. Albert and his wife, however, are newlyweds. They don't have a lot of spare cash. Nevertheless, their attendance at these family events is expected.

I believe to charge a guest money to attend a gathering like this is a social blunder. Albert says that's the price of marrying into the family. What do you think, Abby? -- PROTECTIVE SIBLING, NORTHERN CALIFORNIA

DEAR PROTECTIVE SIBLING: Considering the fact that the in-laws have money, the practice is certainly unusual. However, your brother knew what he was getting into when he married into this family, and you should M.Y.O.B.

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DEAR ABBY: I am happily married to the most wonderful woman in the world. I feel blessed to have her in my life and to be a part of hers.

I am not an elitist; I like to think I am a humble person. But I do believe in correct grammar, proper pronunciation and the eloquent employment of words in conversation. My wife did not have the benefit of an upbringing in which these were practiced. She comes from the "ain't got no" school of speaking.

I can accept this at home, but in business as a corporate executive, I am embarrassed by her low verbal skills.

I would never hurt or shame my wife by correcting her in front of anyone. The obvious answer is to bring it up in private. I did that, but she is not inclined to improve her word skills. She has mentioned a friend who tried to help her in this endeavor, but it went nowhere. I wish I could do something. Any ideas on how I can help? -- WORDSMITH IN ILLINOIS

DEAR WORDSMITH: The most important line in your letter is the one in which you say you have spoken to your wife about the problem, "but she is not inclined to improve her word skills." You might try one more time, and tell her you're afraid her poor English will affect your chances for promotion and you would appreciate it if she would take some courses in English grammar and literature. But you can't force her.

You say you have a happy marriage and your wife is the most wonderful woman in the world. Nobody has everything. Love her for who she is and stop worrying about how others perceive her.

DEAR ABBY: I have had terrible luck lately at fast-food drive-through restaurants. I eat on a budget, and I'm getting tired of pulling away only to find my order is incomplete -- or worse, inedible.

My husband says I should check the order before I pull away, but I'm afraid it would be rude because it holds up the line. What do you recommend? -- STALE BURGER BUNS IN ILLINOIS

DEAR S.B.B.: Fast-food restaurants do not always have experienced help. That's why it makes sense to check your order before you leave as your husband suggested -- and doing so is not "rude." However, there is no excuse for a customer being served stale or improperly cooked food. If that happened to me, I would complain to the manager, and if it wasn't corrected, I'd take my business to another establishment.

DEAR ABBY: I have had terrible luck lately at fast-food drive-through restaurants. I eat on a budget, and I'm getting tired of pulling away only to find my order is incomplete -- or worse, inedible.

My husband says I should check the order before I pull away, but I'm afraid it would be rude because it holds up the line. What do you recommend? -- STALE BURGER BUNS IN ILLINOIS

DEAR S.B.B.: Fast-food restaurants do not always have experienced help. That's why it makes sense to check your order before you leave as your husband suggested -- and doing so is not "rude." However, there is no excuse for a customer being served stale or improperly cooked food. If that happened to me, I would complain to the manager, and if it wasn't corrected, I'd take my business to another establishment.

What teens need to know about sex, drugs, AIDS and getting along with peers and parents is in "What Every Teen Should Know." To order, send a business-sized, self-addressed envelope, plus check or money order for $6 (U.S. funds) to: Dear Abby -- Teen Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included in the price.)