Many things can not work right when the foundation of hormones is not. He should get a male hormone panel, including TSH and fT3, fT4. Depending on how he does during the day, energy wise, he might need some cortisol testings. Repeated surgeries can contribute to, or cause, adrenal problems.
Have you looked at his nutrition and supplements?
Fasting serum glucose?
What Rx and OTC drugs that might be causing problems?
Statin drugs without CoQ10 - muscle pain?
Signs of low testosterone, such as hair loss below the knee?
Fish oil and high dose vitamin D are a good foundation, as well as the usual supplements.
I guess that he needs to look at the hormone situation and look for fundamentals. This goes beyond physiotherapy. Healing is complex and ca catabolic state makes the outcome a bit grim.