I am trying to obtain info on the process of evicting my newphew who lives with my sister and her husband who is seriously affecting my sister's health. She suffers both mental and physical disabilities and has deteriorated tremendously ever since my newphew (33yo) left work 2 1/2 yrs ago. He has been in 8 accidents with their cars, even totalled one. He causes such scenes that they end up just giving in especially because he knows he cannot be thrown out. There must be some special consideration given because he is such a detrement to his mother. They have little money to afford an attorney so I am trying to obtain whatever info I can... thanks

What state are you in? You can contact the small claims court and get information on evicting a tenant. Your sister and/or her husband must be willing to pursue this.

If he isn't paying rent he's not a tenant. If he's not a tenant you can tell him he has to leave, give him a firm deadline. Once you informed him he is no longer welcome in the home he's a tresspasser and you can call the police. It will be hard for your sister to do this I'm sure but he's an adult now and at 33 he has no reason to be living at home.

Of course if he is paying rent this is another story...

I know it can be hard to feel like your just standing by as this happens but you need to remember that your sister is married and by the law it's their problem. You can only make suggestions but at this point unless there is physical hard or coersion then you can't step in on their behalf and get the ball rolling.
Also you might check if she is in need of socail services and what they can do for her.

Why can't he just be thrown out ? Many people just change the locks and set their kids things out on the porch, heck I have done it before myself with a 18 year old son. Hated to, but of course they can just throw him out.

If he has some rental agreement and was paying rent, you have to file in court to have him evicted legally,

But the parents will have to throw him out or file for a eviction.