DEAR MISS MANNERS: Is it disrespectful to bring an ex-girlfriend to see her ex-boyfriend, in front of the current girlfriend, while the ex-boyfriend is in his last days of life?
GENTLE READER: One should comply with the wishes of the dying, if possible.
This often requires restraint on all sides, and possibly discomfort. It certainly requires knowing what those wishes are -- which is not evident from your question.
The ex-girlfriend does not have a right to a final visit, and so must make a request. If a visit is to occur, the current girlfriend could be gracious by excusing herself. Miss Manners is unclear of the identity of the person “bringing” the ex-girlfriend, and reminds him or her that this is not an area in which outside judgments about what is fitting will be welcome.