Re: How to advise
Why are you assuming that her family is so dumb that they will get her married to a family which will not take good care of her ? I am sure her dad who has taken care of her for so long will make sure that she is married in a family which will take good care of his daughter .
You are being judgmental of the father who has spent so many years to raise this girl , it is not easy to raise normal kids let alone kids with disabilities and challenges. He will be highly rewarded by Allah inshallah for all the sacrifices he had to make to raise this girl.