I would like to suggest to always get the money part worked out before hiring or even allowing anyone to do a job. Even though this man offered to do the work and didn't ask or mention anything about money, had it been me, I would have asked him...."and how much will this cost me?" Never be shy about getting the money part straight before having the work done. It's your money and you need to protect it.
As for having him move in, I strongly urge you not to do this. You have heard all the stories about predators and so forth and it really doesn't matter about age or appearances because these guys just want to get inside your home. He may be the nicest man in the world, but at this point, you don't even know his name, do you?
Someone on this board wrote a post that asked the question "Are People Less Trusting Than They Used To Be?" And, we have all heard the phrase, "Trust your fellow man." To that I say, "Bunk." Personally, I don't trust anyone that isn't close to me. A person either has to be ignorant or blind if they can't see what's going on out in the world today. The stories I could tell and if I did tell, you would be sleeping with the lights on tonight. The world has become a very dangerous place and for those that don't believe that, they are what we call an "at risk person" or "ARP."
Now, go have some fun.