The rest of the visit was mostly as expected: we went to a zoo and a museum, my mom reminded us of the existence of gift shops every 30 minutes or so during those trips, but we enjoyed the trips anyways. On the last we went shopping (and looking at kittens) downtown, and actually that was pretty fun, Oberlin has some neat art galleries.
During one of the museum gift shop visits, apparently my mom and dad got in an argument over something that she wanted to buy (I think for the other grandkids?) that he thought they wouldn't like at all. I was outside of the shop, though, so I don't know exactly what was going on. And it must be difficult for them to negotiate that sort of situation: sometimes my mom needs my dad's help to do something, and sometimes he doesn't want to be part of that something. If she could see, she could just do it, he wouldn't be part, and it would be a normal disagreement; as is, though, it gets more complicated. In general, what I think happens is that he does that thing anyways, and in general I think that's the best outcome, but I don't think it's always the best outcome, and I got the impression that, in this situation, the discussion about the outcome didn't play out very well.
Also, on the last day, at some point my mom and I talked for a bit, and I said something like "we'd been having arguments about shopping all week"; if I'm remembering correctly, she said something like "really, I didn't realize that". That felt pretty odd.