How To Treat A Polio Affected Leg That Is Going Weak?

My brother who is 32 yrs old 6" height with a sound health having polio in his right leg from his childhood. Day by day his affected leg is getting weaker.Sometimes the muscles is getting tight and it pain a lot that time. And the affected foot also pain sometimes. He gets tired even in a short walk, and pain starts .His leg pains and muscles get tight though he does not walk much . Please advice me any good doctor, medication or exercise which wil be fruitful for him.