I think she was especially stressed out about his weak health and didn't want to have anything else to stress about. So she ignored it and this issue developed. I realize that parents are usually like this after I've experienced something similar
She was definetly already stressed but she just brushed his sexuality under the rug when he was genuinely confused and reached out to her for help :(
And yeah unfortunately a lot of parents are but it's changing with new generations. But culture also comes into it, my religious parents would've sent me to a religion-based school if I had asked that question instead of public school (where thankfully I learned it was normal). I was slow so even after sex-ed it still took me a while to realize I liked girls lol
I really hope a change comes soon to end this stigma
But I guess I shouldn't have much expectations for humans ╮(￣▽￣)╭
Urgh, parents like that. This is why a lot of gay folks take forever to realize their sexuality and grow up feeling confused like they're abnormal for not talking in love with the opposite sex or for feeling attraction to the same sex. Imagine if his mom had helped him out, used it as an opportunity to discuss what sexuality is, helped him sort out his feelings etc.