@diana97,
If he is suicidal, then he needs medical attention. I realize you're saying that he is receiving medication, but sometimes antidepressants can do the opposite of what they're supposed to. I suspect depression; it can do all sorts of things to someone, including making it hard for them to sleep, or to sleep when people normally do (e. g. the middle of the night, instead of afternoon napping and maybe nothing else).
If his current doctor won't give both of you satisfaction, go to another one.