Bummer. Too bad it's past Christmas, and I've already given him a new mouse, this might have been a really decent mouse for him. The thumb buttons wouldn't have met his criteria, but I don't think anyone makes a mouse that fits his criteria. He wanted a mouse where he wouldn't have to move his thumb in order to click it, much like the old style Logitech/Microsoft mice from the early 2000s.
I don't think they make them like that anymore because too many people were accidentally clicking the button and for some inexplicable reason he's too lazy to move his finger a few millimeters upwards to click a button (maybe he's got some arthritis he's not telling anyone about?).
I ended up getting him a Logitech M500, just like his old one as he's old and cranky and doesn't like change and because he ended up telling me he didn't much care for the idea of his mouse giving out on him in the middle of doing something important.
Oh well, I managed to get him a mechanical keyboard for Father's Day a couple years ago and he really likes it, so I'll consider that a victory enough. It was hard enough to get him convinced that me spending $170 on a keyboard was a good idea, thankfully he's fully convinced on the value of a good mechanical keyboard.