I'm accompanying my dad on a trip to rural Illinois to see my 103 year old grandma who although in declining health is still very much "there" mentally. It's a painfully awkward situation for me and I'm sure her also because we don't really know each other and have absolutely nothing to talk about. I've only seen her a few times in my life spaced many years apart, but she still sends birthday and Christmas cards every year and has old pictures of me all over her apartment. I think she's looking forwards to our departure so she can go back to her elderly peers.
My strategy is to limit myself to a few hours a day in her presence and focus on work the rest of the time. For those few hours I need something to talk about. So far I've asked her some questions about her childhood, ancestors, prohibition, WW2, the Great Depression, and life on the farm, which got her talking for a while. History and ancestors/relatives are pretty much the only things I can think of. I'm genuinely interested in my grandpa, who died about 40 years ago, but I don't want to upset her. I've got two days left and need more material. Throw me some ideas.