Check out dynamind.Com & things like ces or sound/light machines & see if maybe you could get him to usee one of these, my dh will never listen or accept advice or take meds or anything - but he was getting migraines & so finally agreed to try my ces machine & hey presto now he wants one too!!
These machines may not solve your husbands problem & in fact may not be of use but I think it could be worth looking into as they help depression, pain, migraines, sleep disfunction, anxiety, suicidal thoughts etc etc so if he has any pain or something that you could get him to use one of these for (or if you have a problem which you could use it for & let him see the help you got!!) then maybe it would also help in other ways.