What’s up with mentally childlike characters?

I have been watching Ghum season 3 and they have a childlike adult character in here too. Idk if she was in the original Bengali show they are copying or not, but I have noticed that lots of shows are incorporating mentally challenged characters but never doing justice with their characters. They are always boiled down to having to get married and give birth like every other ITV characters. There is never a focus on their struggles or what made them the way they are. I know people talk about Aapki Antara for dealing with an autistic character but are there any other show that highlights the challenges of people in the autism spectrum?? I am so tired of them randomly making the ML’s sister or aunt be mentally disabled or childlike and revolving their arc around a lover and then getting them married off and calling it a day. Like what the fuck?? I heard Neel is supposed to marry Aditi but Aditi runs away from the wedding so he married Teju. How are they gonna show all this when Aditi is a literal child in the head? It always feels so icky when they get these mentally childlike characters married. They don’t even understand what marriage entails. It’s the same as child marriage which is highly illegal and disturbing. I mean yeah they deserve to live a normal life too but why does normal include marriage and having kids? As someone who has a nonverbal autistic cousin, it is a topic that is close to home. She is a child mentally and will always remain as a child, not understanding anything around her. I could never imagine marrying her off. She will always need someone to take care of her and that will most likely be her parents or maybe a nurse in the future. I know these shows are fictional but I wish they dealt with sensitive topics like this properly.