Would your husband allow you to go to a pdoc appointment with him?

It could be useful to get a mental health professional opinion - PROVIDED that your husband agrees.

And on another note. Is he open and honest with you when he IS going through a depressive phase? Does he actually communicate this to you?

If he's depressed, show him support.

If he's mentally well and just sleeping because of the hell of it kick his royal hiney out of bed.

Learn what his depressive symptoms are. Sleeping wouldn't be the only symptom. Unless it's a side effect of meds he takes. Hence I suggest you do a combined appt with his pdoc.