Will letting my brother-in-law move in with us ruin our marriage?

My brother in law is 22 and lives 3 hours away with my mother in law. My mother in law has had it with him so she is getting a new place with only one bedroom. He has sisters and cousins in town but nobody wants to take him in. My husband suggested he move in with us and he could go to school (which he hasn't done on his own yet), find a job, and get his life together. He hasn't worked in about 2 years (his own choice), lost the last 2 cars he's owned, and was pretty much living for free his entire life. He has some bad habits that I believe prohibits any motivation. I want to help him but I don't want him to get stuck living with us. I suggested we find him a room in someone else's house/apartment, and we could pay for it...to save my sanity. But it might take a while since he looks rather intimidating, has no job, no references, no credit, ect. I have been married for 3 years. Has anyone gone thru this and how was the marriage affected?