All the work I'm doing for my dad drives me crazy. When will it be enough?

Everyday I say to myself I want to give up and let someone else do all the work. I promissed my mother I would take care of her husband and not put in a home. He has lied about so much and his health is deteriorating due to smoking and drinking. I stopped enabling him and he is still finding ways to get cigarettes. We go to doctor and he tells lies about his health and he doesnt smoke and how he cant see. I mostly just yes him to death tnd tell the doc the truth.
Im guessing doctors know elderly people dont tell the whole truth cause it seems like no big deal to them.
I cant stand that all the work i do to keep him healthy makes me crzy and then he can lie about stuff that is so petty, like he doesnt pick his nose and doesnt know why its bleeding. or I dont smoke. i have trouble seeing i hate the cold but i can go out side for freash air and throw other peoples half burned cigarette butss all over the drivway.
The latest is he has a shrapnel injury from vietnam. I got his dd-214 to try and get more benefits for him that states he was in a hospital in staten island for 3 years as a medic. No combat wound not even any time out of the united states.