Should I stay or should I go?

Instead of leaving him, look for some help. There are organizations that will help with his care. Check with Social Services and the local hospitals. Ask your doctor for some suggestions. You are too young to be burdened by so much. It's a great thing you are doing, but I think you will regret leaving him if you walk out. You sound like you might get a guilty conscious. Try to get his family to help. Ask for volunteers. Make a schedule. Whatever you do, get out sometimes and enjoy life if you can.