One could imagine him thinking about him taking the job as a sacrifice. He will sacrifice his morals and what he cares about for the security of his family and children. He knows that he will sell his soul and be crushed, but he also knows that his family will be okay.

It's one of the reasons suicide bombers blow themselves up too.

But, as in this case he will live and it ignores the lasting psychological damage on those around them - becoming malevolent will affect the people around, and not in a good way.