I dissagree: he hates his job, that is what is producing the stress in the first place.

Otherwise he'd be happy keeping a job and having the weekends for his own projects.

But this is obviously not the case.

My impression is that he is comparing himself to others and worrying about other developers working weekends, possibly making him look bad if he does not do the same. The reality is that the “weekend warriors” at the company are doing more of the same type of work while he would be working on other tech of his own interests on weekends if desired, broadening his knowledge of other toolsets and methods, which will prove quite valuable in the long run.

Quit worrying about what other people are doing.