There are some breathing exercises taught through Tai Chi which concentrate on the diapragm. They are very gentle. This would be unlikely to heal the situation but it might do some good. The exercises are learned slowly and done slowly and are very relaxing. And they can be done at any time and can give a person something to do while lying in bed. If you are in the Boston area, call Brookline Tai Chi. The exercises are called Longevity Breathing and have to be taught by an experienced practitioner.
This is a terribly difficult problem. The use of CPAP during the day as well as at night might be helpful. Bilateral diaphragmatic paralysis can be caused by multiple sclerosis, thoracic and cervical spine surgery, muscular dystrophy and various diseases of muscle called myopathies. If the phrenic nerves are still "firing", some type of muscle disease would be likely. This would be consistent with his inability to support his head. You should talk with his doctors for suggestions about how to deal with the problem of inadequate head support. You could try using some type of head harness or simply a broad band around his forehead and attached to the head of the bed.
There are no reports of Zyprexa causing this type of problem.
You are most welcome. If the nerve is firing, then these exercises will help him maximize the function he does have. I learned them as part of a medical study re asthma. If you are having no luck on line, please call Brookline Tai Chi in Brookline MA(recently changed name to Water Way Arts or something like that). They may be able to help you find someone in your area. Best of luck.
Thank you Rosie for your feedback. We live in Wisconsin. I will look this up on the internet and see if there is someone in the area that can teach this to him.
Thanks again.