Id give him a little time. Most people I know that buy a car thats not going to be daily driver. Usually don't tag it until they sell it or start driving it. Here we have to have insurance on the vechile just to change the title over. I don't think not having it changed into his name makes him a bad trader. Most people dont realize how hard it is to get title work done, hes probably finding that out right now. MV always finds something that you have to go back and do.
I'd give him a little time, but don't let your guard down.