My advice is like most people say, cut all ties. His problems are not your problems. I have had a lot of 'friends' steal things from me and i cut them of straight away. They never admit it and they never try to make it right, some people just have no conscience. Tell your other friends never to ask him around to yours again. If you turn to violence (you don't seem like that kind of person) he may very well turn the table on you and involve the police.
Good friends are hard to come by and he is not one. I am 42 and still make mistakes with the kind of friends i choose. Go with your gut instinct, but a thief that steals from a friend will do it until you cut the ties. Never feel guilty for doing this, he won't he will just move on and steal from someone else.
As for the suicide stunt, most people don't talk about it they just do it out of the blue. He just wants attention and that is not your job, give your attention to your wife and forget about him whatever the outcome.
