OK, here's an update. First of all, remember that my dad is 85, a retired physicist who never used a computer in his career. Other people did those things for him.
Anyway, I had to talk him through the installation by phone. The thing is for PS2 connections, so it needs a PS2 mouse of all things (included) and a USB adapter, also included. Sounded like he had it hooked up right. This was several weeks ago. And he told my sister who lives nearby that he thought he really was making fewer mistakes on the computer. But then we discovered that he had never disconnected the Apple mouse attached to his keyboard, and had continued to use it, instead of the one hooked up to the adapter. Sheesh. And we also discovered that he had the USB adapter plugged into a hub, and it can only work plugged into the computer's USB port.
So now it's actually working, and he's using the mouse attached to the adapter. He's going to experiment with it. No word yet on whether it helps, but hey, it was a fathers' day present, and we never know what else to get him.