It sounds like he's no longer capable of making rational choices, so you will have to. Think of what you'd do with a two-year old who wanted to poke a fork in an outlet. Would you let him? Of course not. He might holler and cry big tears, but you'd know you were the grown up and knew what you were doing. Same with your dad. He's no longer the boss of you. It's difficult when the roles get reversed but don't feel guilty for doing what's necessary, no matter how your dad feels about it. This is too much for you to do alone.