Good luck with that. I can't see a teenager taking kindly to be excluded from lessons, talks etc on LGBTQ+ subjects, and in fact I question how it can work given that those topics can come up at any time in a variety of lessons.
I can! DD does not have autism; but does have considerable complex learning disabilities, due to a congenital brain abnormality. This includes rigid thinking. Really she found seeing heterosexual kissing disgusting, gay kissing was even worse!
She had to do LGBQT+ in sex education, and she complained to me every week how disgusting it was! I don’t know what they thought they were trying to achieve; but we told them, she didn’t get these views from us, she developed them all by herself; but they wouldn’t change her views by any amount of talking and it would only cause distress! None of the students were expected to be capable of sexual relationships and they only did sex education apparently to give them the vocabulary to complain, if they were ever sexually abused.
She was in a specialist college, where lessons were things like flower arranging, art, woodworking, weaving and materials, PE, cookery, and trips out to cultural places; so it was not true for them that LGT was going to come up in a variety of lessons.