Its hard to comment unless i know more about the situation, like is he last in, where the rest of you friends before etc.
But what I do know is, most people are who they are, you might be able to alter his actions a little through heart to heart chats, but the bottom line is, mostly you have to take people at face value and decide if its worth it (good vs bad points), if not resolve it quickly for the sake of everyone, even if that means parting
You mention he will become a Dad, that could change everything anyway, but again that will depend on the dynamics in his family unit, personally I carried on as normal with outside activities when my kids where young, my wife is cool, but it doesn't work for everyone