To be honest, I'd much rather be a stay at home parent than a working parent. My dad was a stay at home dad and my mom worked full time, my mom started to resent my dad. My sister was a stay at home parent and her husband worked full time, he started to resent her. This is actually very common these days. If one parent gets to stay home, the other parent starts getting jealous.
Hopefully he does go back to school, but the kids would still need daycare if he does attend classes. Hopefully he also tries to look for a better paying job with better hours so he isn't exhausted all the time when he goes back to work.