DEAR ABBY: My brother's daughter will be married at 8 p.m. on a Saturday night. The invitation insert card has "black tie" written on it. Abby, my sons do not own tuxedos and cannot afford to rent them. When I explained this to my brother, he informed me that all men had to wear tuxedos, and if they did not, he would take it as a personal insult. Needless to say, I was shocked at my brother's attitude and told him so.

Abby, I want to know if it would be permissible for my sons to wear navy blue or black suits. I don't wish to offend my brother, so should my sons not attend their cousin's wedding unless they can come up with the money to rent tuxedos? My sons are very close to their cousin (the bride) and it would sadden me if they did not attend her wedding. What would you do? - SISTERDEAR SISTER: I would advise my sons to wear white shirts and formal bow ties with their navy blue or black suits, which very often pass for tuxedos. I assure you, very few people would notice or even care - with the possible exception of your brother. And since he would take it as a personal insult if your sons dared to appear in anything but tuxedos, why doesn't this pompous snob offer to pay for the rentals?

DEAR ABBY: Please print this in your column. If it helps just one person, it is worth it.

I am serving a 13-year prison sentence in Texas for armed robbery. It all started when I was 15 and succumbed to peer pressure to smoke a "joint" - marijuana. By the time I was 18, I was drinking every day and doing hard drugs. These last five years have been a living nightmare in my fight against alcohol and drugs, but I couldn't or wouldn't stop until I was locked up.

Abby, I am 31 years old. Prison life is very hard. Every ounce of freedom is taken from you. When your loved ones come to see you and you have to talk with a glass partition between you, it tears your heart out. I have a hard time trying to forgive myself for what I have done to my parents, my wife and kids.

A message for your readers: Please, if you are a young person, don't let peer pressure get to you. If you have to break the law to be "in" with your friends, find new friends. If you have already started to drink or do dope, get help. Any kind of help. Just get it. Don't say you can handle it. That's what I said. - SOMEWHERE IN THE TEXAS PRISON SYSTEM

DEAR SOMEWHERE: Maybe - just maybe - you turned someone's life around. Thanks for writing. Good luck and God bless.

DEAR ABBY: My friend and I are having a little dispute. When are you categorized as a teenager? - DISPUTING IN CALIFORNIA

DEAR DISPUTING: When a person celebrates his/her 13th birthday, he/she can be categorized as a teenager. One is no longer a teen at age 20.

By popular request, Abby shares more of her favorite recipes. To order, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: More Favorite Recipes by Dear Abby, P.O. Box 447, Mount Morris, IL 61054. (Postage is included.)