Hello Terry,
Like the others here I am very surprised his diagnosis is CRPS as his symptoms are quite atypical.
There are a multitude of problems that can cause his abdo pain and I really hope you can get on track with someone who is willing to do whatever tests it takes to make a proper diagnosis.
His weakness in his legs may well be just from the fact he has become so out of condition from his chronic illness
It may well be also a reaction to his medications. They are obviously not helping do anything for his pain
I wish you luck with your son, please let us know how you go.
Take care
Tayla