Wow, you *both* have gone through a lot.
As for your husband, one cannot diagnose anyone else, but it would help for him (maybe you as well?) to seek mental health support. Your husband has lost a lot of people and that does impact one's mental health.
You also have gone through a lot personally (your medical scare, losing a child, seeing your husband's struggles). So, I hope you also take care of yourself i.e. both physical and mental/emotional health.