I am in the same boat with Jim. I am tired when I go to bed and tired when I get up. I stayed tired and I talked with my family doc about it and she said it would take more than 2 years for my body to bounce back completely.
As far as him being in the bed 15 hours a day I would say hes doing very well not to be inthe bed longer. I especially remember when I had a chem treatment. I would sleep for 4 days straight. Look for the sleep time to get longer before it gets shorter. As has been already stated, the best time to heal is when the body sleeps.
Billy