DEAR ABBY: My son got into serious trouble and is in jail right now. He is 19 and began getting into trouble with the law three years ago. He's close to his grandparents, who live out of state, and when he first got into trouble at age 16, I kept them in the dark about it as long as I could. They eventually found out, and I know they worried a lot.

My son stayed out of trouble for more than a year. He went to counseling for alcohol abuse and other problems. I realized he still had problems. But three days ago, he and a friend of his broke into someone's garage to steal and were caught. My heart broke once again. My son is now in county jail. I visited him there and managed to hold back my tears in front of him, but I cried all the way home.

Here's my problem: Should I tell my parents, who are 1,000 miles away, and cause them all this grief? My mother telephones every weekend to "check in." I didn't have the heart to tell her this Sunday. Do you think she has the right to know? She always asks about her grandsons and is especially close to this one. I just don't want her to worry. -- BROKENHEARTED MOTHER

DEAR BROKENHEARTED: Since your mother always asks, and feels especially close to this grandchild, I think you should tell her the truth now. Eventually she will have to be told, unless you intend to deceive your parents about the boy's whereabouts until he's served his time. If so, your chances for pulling it off are slim.

DEAR ABBY: Please discuss fathers tickling their young children. They seem to get some sadistic pleasure out of expressing their love (?) by tickling the little girls and boys until they scream with laughter, then pain -- then end up in tears!

This needs discussion, Abby. I think it's sadistic! Do you? -- MRS. B. IN JOPLIN, MO.

DEAR MRS. B: Yes. Children who "end up in tears" are experiencing pain -- not pleasure -- and no father should be permitted to play such games. Excessive tickling is said to stimulate children inappropriately. To subject a child to this kind of "play" is child abuse. It's the business of adults to protect children from ANY kind of child abuse -- and while it may appear innocent and "all in fun," it should not be tolerated.

DEAR ABBY: The woman who was upset because her husband's friend held his fork incorrectly just about sent me through the roof. I wish all I had to worry about was how my friends held their dinner forks.

I'd like to tell that woman that if more people would hold their forks in their fists like a 3-year-old child, but were smart, college-educated, well-mannered and had great personalities, our country would be much better off.

I suppose a man could be a rapist, murderer or drug dealer, but as long as he held his dinner fork properly, he'd be OK? That woman should come down from her pedestal and start dealing with issues like world peace, abused children, caring for the elderly, and feeding the homeless -- who would be happy just to eat, let alone hold a fork properly! -- S.B., ROSEBURG, ORE.

Abby's family recipes are included in her cookbooklet. Send a long, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Cookbooklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)

DEAR ABBY: I am writing this from a well-known cancer and tumor clinic in Texas.

We are here because my husband, who has had a complete physical every year since 1971, has inoperable prostate cancer. I am angry and bitter because no doctor, during 20 years of annual physical examinations that included a digital rectal examination, ever mentioned that there are blood tests which can detect prostate cancer.

We have been told that my husband has had this disease for at least seven to eight years. We also learned that if a man's brother or father has had prostate cancer, his chances of getting cancer are increased 2 1/2 times! In every medical questionnaire my husband has ever filled out, he stated that his father had died of prostatic cancer. (His brother was diagnosed last week with the same disease!)

We are hoping that our experience will educate others so they will not find themselves where we are. We strongly urge all "high risk" men to be examined by a urologist, because many physicians do not recognize prostate disease. -- ANGRY AND BITTER

DEAR ANGRY AND BITTER: You have every right to be both angry and bitter, and I thank you for trying to warn others.

For readers who do not know what "high risk" means in this context, it refers to people whose blood relatives have been afflicted with the same disease.

DEAR ABBY: When a couple asks another couple to ride along with them, what is the proper seating? Should the wife automatically sit in front with her husband, or should she sit in the back with the other lady? Or should the couple whose car it is ask the other couple how they prefer to ride? -- EDNA C. IN CARMAN, ILL.

DEAR EDNA: It depends on the circumstances -- how well the couples know each other, the distance to be traveled and whether either of the couples are newlyweds. (Newlyweds usually prefer to sit together.)

The important factor in the seating arrangement is that everybody be pleased and comfortable. Couples who have a long friendship might prefer "one-on-one" conversation with the spouse of the same sex. My personal rule of thumb: When in doubt, sit with your own mate.

DEAR ABBY: Thank you for insisting that a written thank-you note for a gift is still absolutely imperative. I was appalled when a reader suggested that a "warm hug and a verbal thank-you at the next chance meeting at church or a social function should be sufficient."

A child should be taught at a very early age to write a thank-you note. Writing improves finger coordination, penmanship and spelling, and helps to create a bond between the child and the giver.

In today's world of electronic communication -- the telephone and fax -- it is still necessary to record thoughts, events and instructions in writing. If a "tape" is erased, the message is lost forever. Therefore it is vital that we learn how to communicate in writing. And it all begins when a child is taught to write a thank-you note.

At 86, I am still writing. -- M.S.P., SANTA ANA, CALIF.

To get Abby's booklet "How to Write Letters for All Occasions," send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Letter Booklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)

DEAR ABBY: I am a 13-year-old girl. I have a sister who is 19 and has been married for a year. One day last week, her husband told me how beautiful he thought I was and how much I had developed lately.

Later he gave me a ride to my girlfriend's house to pick up my bike. On the way back it was quite dark. All of a sudden he stopped the truck and asked me for a hug. I thought, "What the heck, he did me a favor to drive me to pick up my bike, so it's no big deal to give him a hug." Well, it was a real long hug, and he wouldn't let me go. Then he asked me for a kiss, and I said, "No way ... no, NO!" He knew I really meant it, so he let me go. Neither one of us said a word until he dropped me off at my house.

I really feel uncomfortable around him now. I can't tell my sister or anyone else because my sister really loves him and I couldn't live with myself if I made trouble in her marriage.

If you want to print this to warn other teens who may run into a problem like this, please don't use my name. -- THE KID SISTER

DEAR SISTER: You were very, very wise. Thanks for sharing your experience as a warning to other young girls who could be taken advantage of by a relative or close friend.

DEAR ABBY: We got a good chuckle out of "Very Disappointed" who spent her wedding night on a fold-out couch in a fancy hotel. Your advice to double-check reservations was very good, but it doesn't always work. Here's our story:

We had arranged the "honeymoon package" at the then brand-new Hilton in Erie, Pa. We arrived late on our wedding night and were warmly welcomed at the front desk. When we got to our room, we found the promised bottle of champagne and a very lovely large room -- but no bed! It seems one of the couches was a fold-out bed with one pillow and a set of sheets (no blanket)! When we telephoned downstairs, we were informed that the hotel was full and "housekeeping" was closed for the night, so we were out of luck.

When we folded out the bed and sat on it -- it collapsed!

But what the heck? We've had many laughs over that story through the years. We've often said that a couple without a sense of humor could have broken up over such a series of incidents. Let's hope the honeymoon couple in that classy Dallas hotel survived their disappointment.

As for us, 13 years later, we're ... STILL LAUGHING IN GRASS VALLEY, CALIF.

CONFIDENTIAL TO V.N.: You know you're getting old when a lady you've never met before is seated next to you at a dinner party and she asks which is your good ear.

Want your phone to ring? Get Abby's booklet, "How to Be Popular" -- for people of all ages. To order, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Popularity Booklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)