I Need My Dad Out Of My Home - But He's 64 And Disabled

Location: Alaska

My mom bought a house for my dad and brother in another state. She left, but my dad and brother just... didn't. She was the breadwinner with my dad on SSDI and my brother helping take care of him (several bouts of cancer, both arms unusable in need of rebuilds, slipped discs). Getting around and being functional is harder for him than most.

I let them move in with my boyfriend and I, as we bought a nice 3 bedroom home and I don't want them homeless and in the cold. Neither pay any rent and we have no written agreement in place, I just wanted to help family out and figured I'd get some money thrown towards food and maybe some chores helped with.

My brother is great, my dad is a problem. He steals to pawn things and denies it, makes a total mess of my home - Grease stains everywhere, throws trash wherever, makes a mess of the house. He's always naked in the house and I can hardly get him to wear clothes. He leaves and comes back sometimes acting weird, and I suspect he's on some kind of substance. I can't host my friends and colleagues anymore for get togethers due to this and his foul moods/treatment of them. He's also becoming verbally abusive and calling me names, just saying manipulative and horrible things.

He's starting to feel entitled to wreck my home and do as he pleases, put me down, and I'm feeling like a prisoner. He's also guilt tripping me into giving him money, even with the thefts I can't prove but know he has to be committing. I told him if I had to evict him I would if he can't act more decently, but he told me the court will never evict a little old man who can't do for himself, and that he'd fight and appeal over and over if he had to, but that he likely wouldn't due to his documented disability.

How much if this is true? What would an attempted eviction look like in this instance where he'll look to the court for sympathy and likely change his whole demeanor to be a sweet innocent guy? I'm scared to even try... but my life is becoming miserable... I can't start a family with this man around...