Suggest Treatment For Chronic Ulcers Below Knees

Hi, my father in law has been suffering from chronic leg ulcers from the knee down to the ankle. He has seen many physicians and they have all told him there is nothing left to do, but I don t believe them. He is living in constant pain and I need to find something that will help at least reduce the pain. Is there anything we can do, like go see a skin specialist? Or someone who specializes in veins/circulation?