I think you should find a group setting for him for his sake and for yours. I think you should also attend a support group that will make you realize that somethings are beyond our control and it is nothing to do with selfishness. What kind of a lesson are you teaching him if you are being brutal to yourself?
You don't want to do that do you? Also in a group setting they may be able to safely experiment with a combination of drugs that might help him and stabilize him. Obviously, the medication he is on now isn't helping. Sometimes acts of kindness in the beginning look like cruelty but in the long run are loving acts...show him how much you love him!
Bobby