I have a 16 year old Junior this year. He mostly eats the cafeteria lunch. Rather he picks at it - he eats the fruits, starches and milk. They have horrible food at his school.
Anyhoo, when he packs a lunch he goes with Peanut Butter and jelly, ham, or turkey and a few snacks. He will not do pudding cups, or fruit cups in his lunch because they are not "cool" - though he will them at home. He will do animal crackers, chips, string cheese. Never a hot lunch - thermos' are so not cool. LOL Bottled water only.
He does not carry a lunch box or lunch bag. He is content to toss his lunch in a plastic grocery bag and jam it into his backpack.
Tell your friend to let her boys observe what the other kids bring, and what they pack it in. High school doesn't seem as vicious as middle school was - at least not here.