My Brother Has Been Diagnosed With Polymyositis. Doctors Have Said

My brother has been diagnosed with polymyositis. Doctors have said that complete recovery and regaining of muscle strength is going to take time. Wanted to know what can be the signs wherein we can assume that things are healing?
As he is feeling little tingling in his thighs as if the blood is moving.. So does that give a positive sign?
And also except for the high protein diet, anything else which can be given to him in order to enable his faster recovery?
Thankyou!!