We all have our strange side. I have mine. My novel is a tragi-comedy-adventure through the 60s and 70s, and then slogs along, boring as all get out. You have a good head on your shoulders, and if his daughter does too, her parents couldn't have been total losses, right?

He wouldn't move out of their house, he wants to move in with you, he canceled the move to nearby... is this the typical male who is lost without a female nest?
I wonder invite him to stay with you for about 2 months (assuming he's retired or can work anywhere). That might give you enough time to really learn more about him. LDRs are never a good way to know someone.
As for blaming doctors and/or killing herself - that might be the flip side of blaming himself, a shield to protect himself. But who knows? Maybe it's true. Again, I shouldn't be reading into the man. It just seems that he hasn't accepted her death, and never will the way he's going.

Boring sounds good. Congratulations!

I agree with everything you say--about the daughter and the guilt.

And, yes, he can work anywhere; hence his offer to move.

Will chew on the idea of suggesting he move in for two months. I just thought it would be more sensible to live in the same town for a while and date properly. Plus two moves isn't necessarily easier...

Never accepting his wife's death sounds difficult. If you are right, I'm not sure what that entails.