bd on his back

Question
We have a bd that is 6-8 months old. He broke his pelvis and his tail (yes, we had x-rays taken) but we have helped him heal as best as we can. His tail is very crooked and he has a large hump on his back above his pelvis. He eats and poops and gets around pretty well. We don't have anything in his tank for him to climb on because he rolled off his hammock once and I was afraid of him doing it again. My question is: as of late he has started flipping onto his back somehow and then he can't get himself flipped back over. Can being trapped on his back for too long kill him? We leave around 9 in the am and get home around 4 pm (school and work) and I'm afraid if he flips right after we leave that he will be on his back for hours. He'll try to right himself but we help him turn over if we see it happen. When we've just found him on his back (not having seen him flip) he is always just laying there calmly but with a darkening beard so I know he's stressed. We love the little fella so much that we want him to have a happy, healthy life and I worry so much about him. Any ideas or helpful hints?

Answer
 It could be a neurological effect as the traumma heals.  Have you had a follow-up at the vet yet?  I would have him seen to rule out any residual neurological changes.  You may need to adjust his days so he sleeps later and reduces the time when no one is home to watch him.  I wonder if he is attempting to "glass dance"  which is causing him to flip over.  I would not want him on his back for very long, his lungs ar against his back and to have his weight against them may cause further neurologic damage from possible hypoxia.