Suggest Treatment For Kidney Shrinkage

Hi Doctor - My friend hv a Kidney Shrinkage problem, hv any treatment to come back normal. he is very nurvous , Doctor says this happend due to high BP, He only consult one MBBS doctor. He is takin homeopathy but he is feeling more weakness. Now BP is normal. As per my knowledge definately having medicine to comeout this problem. Can u please suggest. thanks