Joni, lack of sleep can cause depression, and depression can cause lack of sleep (or continual sleep). Has your husband ever tried taking amitriptlyene for sleep? Not everyone can take it, but typically, taken two hours or so before bedtime, it helps us stay asleep, creating a deep stage four sleep. In the beginning, if he does try it, he will be zonked most likely all day for a few (3-4 probably) days. Then that wears off, and he'll just be slightly out of it first thing (for me, a glass of water followed by a cup of coffee gets me into high gear). Amitriptylene helps nerve pain, dries the mouth (some), is not addictive or expensive. Most doctors will prescribe it, as it's been around for ages, if you ask for it.
I think that we work so hard at doing so very little, we do need more sleep. I go to bed right after dinner and am in bed for a good 12 hours, using the computer, watching a movie and reading. I sleep 7-8 hours. I also have to take a nap most afternoons. I think from what you're describing, your husband is getting poor quality sleep at best. I hope that this helps...
Ann