Jimmy is a good guy, but I'm not feeling sorry for him. He has made the decision to pursue a relationship with Drake even though he knows it's uphill. I think he should have stayed for the talk with Richard, so he could point out when Drake stopped listening. I can't help wondering whether Richard was always thinking of Bernadette when he talked about the future and having children, but Drake simply heard what he wanted to hear.
I think Drake is broken and he's at fault for not dealing with his issues when he freaked out about Jimmy having had casual sex with women. But I don't see him as a bad guy and he is trying to be honest about how he feels. Ii seems as if he hasn't had a best friend who wasn't also a lover, so when his world fell apart, he did not have anywhere to turn or anyone to talk to. His ability to trust people was destroyed by his parents and Richard, and his self-worth was trashed by Preston. He may not ever work his way out of this quagmire, and he'll lose more than Jimmy, who'll eventually find someone else to love.
Closure - yeah, I'm not keen on that idea either. But telling Richard how he destroyed someone who loved him, and thus make him feel guilty, sounds like justifiable karma.