Legg Calve Perthes and 2 Capital Slipped Epiphasys

My son was diagnosed with LCP when he was 5 and was misdiagnosed for over a year.He was then pinned in R hip, but doc left it in for 5 years.I took him to another surgeon who immediatly took them out..On check-up from that doc noticed the L hip was slipped, back in for pinning...1 year later took those out, 1 year later slipped R hip, put pins in that hip..On check up from that surgery, screws were too big(1 was almost in groin), back in for smaller screws...6 mo. later screws back out....1 year ago, some experiamental surgery( dislocate, shave down, pin it together, manually rotate leg) couldn't rotate leg, he was already under for 6 hours, and he still has screws in L hip, but 1 is starting to back out..Now he has calf pain, shooting pain from the incision down his leg, and weight bearing pain, and doc is taking his time...Any thoughts???? I just want the best care for him, and doc thinks he may have slipped or herniated discs in spine??? Common sense is telling me that if a screw is backing out(not by much) that it may be rubbing against nerves or muscle, but he thinks not a hurry to take out..I know his medical condition is not common, but if he can still walk or if he is a canidate for hip replacement, should he????