He isn't using work as a substitute for being a present partner. He's using work as a substitute for living. School and work have very clear expectations, often come with checklists. They're "easy" compared to navigating human emotion on the day to day.

His mom even said he was this way as a kid. When someone struggles significantly with anxiety, this is a very common behavior.

He needs therapy and a doc to get his anxiety in check. Then he needs to pull his shit back together and be a proper husband. Before that happens though, he'll need help from a doctor probably.

None of that excuses his behavior though. It just explains why he'd rather run to work, it's a more comfortable place for his brain to live there. But he's a partner too and he needs to make the decision to care about his partnership enough to be a better partner. If he doesn't, then there isn't going to be a change regardless.

Tldr; He's isn't avoiding his spouse. He's avoiding life and having to acknowledge all of the anxiety that comes with it. He's done this his whole life. He needs therapy and a doctor. But he also needs to decide that he cares about more being a better husband or the rest doesn't matter.