Just 'yes' to everything. When we're smokers and drinkers and don't want to give those thing up, if we don't feel too bad to begin with, we just want to carry on as we were. Plenty of caregivers on here will reinforce that, and their frustration/concerns about it.
Just keep coming and asking and doing the best you can--it's all you can do for YOURSELF--and your dad will come to realise a lot of things as events/treatments progress. Just love him and do what you already are, which is doing a brilliant caregivers job which no-one would want.

Brenda