I didn't see that in the later post. I've put regular AC into a casement window, the essential difference was that I had to cut a piece of plywood to fit the open part of the window above the AC. Not hard, but it is more work and something Auntie isn't going to do herself. There are also ACs designed for casement, but they cost more too.
I guess she could buy one of those "miracle coolers" that utilize the latest breakthrough in Chinese technology. You know, like the scammers that sell the "miracle heaters", with the Amish made mantles in the winter...... I think the cooler amounts to an ice pack that you put in the freezer, then put in front of a fan in the miracle unit. Cools for just pennies a day.......