First of all, if you don't trust the guy, then don't do it, period. Secondly, it sounds like the guy is a shameless leech. Asking for help is one thing, but taking advantage of a helper is simply unacceptable. You need to let go of the dude's past image and look at the way he is now. If the guy is really emotionally shaken up by all the events that occurred, they it probably isn't wrong to help the guy out, but, once again, if you don't trust him don't let him live with you. You and your immediate family come first. I'm no psychologist, but that's my two cents.