Ah I thought the sister's backstory would be that she was dating someone and his family di...

I think she doesn't like Will because his father is a delinquent and even if they're nowhere alike but she doesn't know it and just wants to protect her brother
though it's not fair and I'm afraid it'll just damage their relationship :((

Why do people keep ignoring Will was very much the type of guy the sister has experience dating. Will before he met Simon was very much the sort. Will’s own friend has commented on this. We literally saw a chapter of an ex of Will approach him just in the street for causal sex?? simon’s Sister is literally just being cautious because she’s likely dated “bad boys” like Will. Coupled with his mob ties Will is VERY VERY VERY bad for someone like Simon to date who has ZERO life experience, romantic or otherwise. She’s just a voice of reason that is pushy sure enough, but god I’m getting tired of the hate being thrown on her. Just because you like the idea of Will and Simon together because of his cliche it is because it’s BL logic doesn’t mean Will would ever be a good partner to someone like Simon. Simon is perfectly fine to choose his partner himself, but it doesn’t mean he won’t get hurt. But also Will could be completely different now, but he hasn’t done anything to gain the sister’s trust he’s just getting angered himself and being petulant about it which is seen rather than him respecting her role in Simon’s life, he’s backing off due to anger not respect. That makes a huge difference. I worry about the readers clear inability to rationalize the reality of a character of someone like Will and Simon’s sister ad they are just too focused that the plot isn’t moving fast enough to ensure a romanticized happy ending.

Those people wouldn't act the same way about it in real life. They know very well that this is a story, not reality.

I would hope so with the hate being thrown her way