Respond? The only question in there you may want to consider responding to is the question about D? This seems like one of those, less is more things to me. You cannot change his mind. You can leave him his space to figure out how to finish his "do-over" to get himself right.
Short and sweet and to the point - "Yep, I don't want D to stay alone. Here's what I suggest we do...." Everything else you've already said. Don't repeat it. You'll just get angry and he won't take it the way you meant it. Or you'll plead or try to point out what he's doing wrong. He knows all of that. Nothing you can do to help that except live your life the way you want to live it. Lead by example so to speak.
AJ
"Our lives begin to end the day we become silent about things that matter" MLK Put the glass down... "Yesterday I was clever so I wanted to change the world Today I am wise, so I am changing myself."
