Mental health question?

My son is 31. He is physically able to work but can never hold a job. He feels entitled to my things because he's "my son". He thinks anyone who has more money than him should share it with him. He complains about no sleep, bad back, bad knees and he's loud and looks to make sure someone is paying attention to him. He always complains so people feel sorry for him but says he's not looking for pity. He's currently living rent free in our cottage because there's "no work". And sometimes he says hes retarded and thats why he can't work. HELP!!!!!!! Should I try and get legal guardianship and put him in a mens home? Should I throw him out? He has a wife and son who live elsewhere because he won't provide for them and he says he feels real bad about that. Oh, and he lies and gets mad if you don't believe the lies.