What could cause this sleep issue and how can we resolve it?...

...My husband has an extremely difficult time falling asleep, and is nearly impossible to wake up in the morning. He is always tired and grumpy because when he does sleep he says he doesn't wake up rested. He does snore, but not ridiculously. He is often late for work because of his inability to get up in the morning. It takes him literally two hours just to get out of bed. He isn't lazy though, he works 5 days a week, 8-10 hours a day. Its very hard work, he should be tired by the end of the day but he just sits up or lays in bed awake.
We tried sleeping pills, they didn't help.
What could cause this problem and how can we resolve it?
A note- shortly before he started having real issues, (he always had some insomnia) he was in an accident and received a horrible blow to the head. Could that actually cause sleep disturbance? It happened about a year and half ago, and it is just getting worse and worse....

"wow ok well has he stayed up like really late multiple times before?
because if he has then me and him have the same problems because its probly energy that he lost during staying awake and it all adds up so maybe he might need to like take a big rest like only get up when hes ready it works and as soon but strickly as soon as he feels like knocking out he should either go to bed or try to and if it doesnt work the 1st time then he should rest when he cant bare but he shouldnt challenge his sleepyness.there is also a pill that makes u sleep for 16 hours straight i dont know the name but i know that if u do use it for the 16 hours its kinda used like you would take 2 pills instead of 1"
(answered by Alex)