My Husband Has Been Taking 100mg Of Morphine For About

My husband has been taking 100mg of morphine for about ten years. This is a huge concern for me because it doesn't really seem to help with his pain any longer and I would like to help him get off of them. My concern is withdrawing systems. He had a ruptured abdominal aneurysm repaired last year and I am concerned how going through withdrawal will impact this. What is the best way for me to help him? We don't have insurance or I would have him do this with medical supervision.