I'd say yes, it's possible he's lying if that's his history, but also yes, you can actually feel that crappy even one week into treatment ... and then if a craving actually sounds good, you'll jump on it just because everything else is so rotten. And yes, it's totally possible to be both ways at once. I've got a friend who recently managed to leave a relationship like that, and I had no idea what all it had been like for her till she was able to tell me after ... so I can totally believe your story as a possibility, because her husband had serious illness during that time and exhibited similar behaviors. But having been through the rads and chemo ... yeah, I could see that too. Except I didn't feel much like driving ... I'd probably have asked someone to pick it up, if they were going by it. (We have places pretty close to home.)

I am very sorry you are in this situation as caregiver. Is it possible to find respite caregivers in your area? When I had my feeding tube, I was assigned a nurse to check on my nutrition (maybe nurse isn't the right title, but it's close enough), and she actually came to the house to set me up with a IV pole to hang the bag from, showed me how to use formula, and set up an order for delivery of formula. I didn't use a lot, so she didn't come by much to deliver more, but she was there if I needed her. There are probably other sorts of helpers ... the drivers from the cancer society, maybe others? It won't stop any behaviors, but at least you'll get a break from some of it.