Some folk are of the "what's the point in stopping now", especially if its one of their few vices they can still get at. When my grandad had 3 months to live, he stuck to the cigs and whisky till the final hospitalisation. When I mentioned it, he went "Aye, good point, I might get cancer" and then laughed himself hoarse. He'd have found this place funny too if he weren't dead tbh.