There is a device called a Therabite that slowly and gently forces the jaw open. The swallowing PT person should be able to get him one. They also used a Tongueometer on me to strengthen my tongue to swallow better.

My doctor prescribed gabapentin to help restore nerve damage, but my PCP suggested I stop it after I complained of foggy brain. I only had 2 days left and my brain came back to normal after I stopped it. Hope this helps a little.