You know, I got a sister like that. My dad smoked 20-25 cigars a day for 30 years. He quit smoking about 10 years before Alzheimers set in. When I went to the nursing home to see him, he always wanted to go outside or for a ride. The people at the home only took them outside occassionally. When we'd get outside, he'd usually want a cigarette. I'd light him up a cigarette, he'd smoke maybe half and be happy or drop it, whatever. My younger sister would raise hell just like MYH. She'd say I was going to make him sick outside and give him cancer with the cigs.
Before he got sick I heard my daddy tell other people with family that got in his condition, "When they get like that, give'em what they want, make'em happy, even if it kills'ems." So, when I went to see him, if he wanted to go outside rain/shine/hot/cold, we went outside. If he wanted candy/cola/cigarettes, he got'em. ...... and for a little while, he was happy. BTW: none of it killed him.
When my mother got like daddy, her thing was a fish sandwich from HARDEE's or a box of Little Debbies creme filled oatmel cookies. She got'em, youger sister be damned.