you said "leave it go"...lol

But seriously, trying to talk to someone who is in love, about seeing what is really going on in their relationship - is like trying to stop a speeding train by standing in front of it.

I mean, you should approach the topic in an ultra cool, non-confrontation matter [like I know you would ofcourse :)]
but sometimes unless one of the people in the relationship realizes it for themselves, on their own - the advice doesn't go to far.
I don't know though, you're good friends with him so maybe it'll be different. Luv yah.