Hello, your husband is still mourning and may be suffering some kind of dramatic stress, now I'm no expert but I think, if you haven't done so already, sit him down and be stern, tell him that you have noticed the changes in him and you can tell that he's not happy and needs help. Remind him of how things used to be, the good moments you 2 had together and tell him how you feel and how much you care about him and you're afraid for him. I hope this helps, good luck.