I agree that there might be a med that will work, if he has not tried a few different ones that might be an option.
Obviously, many above have commented on weight loss, but since that does not seem to be easy for him, he needs to do something in the meantime. By the way I have a friend who is perfect weight, jazzersize 5 times a week. Hard to control high blood pressure. Genetically bad. Her family has a lot of trouble with blood pressure. Her medication does help significantly though.
Be sure he has had his thyroid checked, a full panel. It could explain high blood pressure and difficult to lose weight. It is a simple, not very expensive blood test for them to check some of the basic thyroid numbers. At minimum they should check T4 free, T3, and TSH in my opion, but I am not a doctor. His doctor may have checked it already. I hope so. Does he have thin hair, need a lot of sleep, dry skin?