Thanks for more explanation. It's really hard to tell what the heck is going on. I'd say it was a bit of both.
Many men that have experienced abuse and watched abuse as children grow up to be abusers themselves. That was my ex. Perhaps your friend doesn't hit, but I wonder what he seems like when he gets mad. I wonder how scary he is?
Carmen sounds like a real winner. It's too bad they had 4 kids!
I'm sure they are both pushing each other's buttons and neither is evil and both are at fault. Typical bad marriage behavior.
What can you do? Not too much. You can be a good old friend. At this point he needs to make up his own mind. I would strongly suggest you resist giving him any advice. Time to just be a sounding board.
Tough situation for your friend. Heartbreaking when a family goes through this. Good luck.