Aware and accepting of his faults, but not blind to them. He's clinically depressed, honest to a fault, and has always desperately wanted to get married and raise a child, which is how he found himself here.
He's not the brightest and makes plenty of mistakes but he's not retarded. I respect him because he's also not an asshole to anyone (complete opposite), is clean/responsible, and is the only decent person to come from his family. Seeing where he came from, it's a miracle that these are the worst of his problems. He turned out alright compared to his dead uncles, locked-up sister, etc.
Disclaimer: Don't take advice from some asshole on the internet.
With that out of the way, your friend sounds like he's suffering from classic "Nice Guy Syndrome". I suggest reading
No More Mr Nice Guy by Robert Glover for a more in depth explanation.
Nice guys...
-Tend to exhibit low self confidence
-Validate themselves through relationships with the opposite sex
-Didn't receive enough positive validation in childhood
-Primarily nurtured by female caregivers / had absent or overbearing fathers / lacked positive male role models in their life
-Tend to have had a lot of turmoil or neglect in their family life growing up
-Learned from a young age that they must please women to survive
-Are desperate to get into relationships
-Will stay in toxic relationships / are codependent / have a fear of abandonment
-Are only "nice" to women to get something in return. Usually sexual validation.
In short, the Nice Guy has a lot of baggage and is only really nice to get something in return. In that sense, he shares a lot in common with his polar opposite: The Asshole. Both of which are equally bad.
Your buddy seems to tick a lot of those boxes from what you've told us about him. Unfortunately, what his wife is doing to him is a form of abuse. She's controlling him, because she knows he won't stand up for himself. The phone call freak out is a classic example of that. She's projecting her insecurities on him. Essentially using him as an emotional punching bag. Perfect recipe for a toxic relationship.
I think it would be very difficult for your friend to stay in this marriage. Bringing children into it would be an even worse idea (assuming they doesn't already have them). He could try counselling, but divorce or at least some time apart would probably be for the best. Teach him that he doesn't need her to feel good about himself. Would probably be like lifting a great weight off his shoulders.
He needs to work on getting his mojo back. That means building self confidence and putting himself before others. That doesn't mean being a jerk. Remember the ideal man is nice because he chooses to, not because he feels he has to. He also doesn't let anybody push him around. The trick is getting your friend to realize that he has a problem and that he can fix it. Would probably help deal with his depression issues as well. Nobody can possibly happy leading that sort of life.
Spending time bonding with other men over a shared interest would probably help your buddy a lot. Does he have any hobbies that have clubs he could join?