Talk to Psychiatry on Depression/maniac Attacks

My brother got maniac attacks since four years. During these times he used to talk too much and got very severe type of mood swings. 2 years back he was in very critical condition and we admitted him in hospital because his condition was out of control. There he had been admitted for 10 days. After that he was recovered. But in last October he again got the problem. I took him to his doctor he gave the same medicine and said he should continue these medicines for at least 1 year. Now he is again facing the same problem. He is not agreed to have sessions. What should we do? Now he is not even willing to go to his doctor for checkup. Please any psychiatrist here to reply and guide me accordingly.