An update: I ended up switching out the cassette for an 11-42, and an extender. Kind of an adventure, since I've never done much with cassettes, etc. It was a good learning experience for both of us. The 11-40 didn't seem to offer enough variation, and at this point in his riding, he needs the lower gears. I think. We'll see today, as he rode to school for the first time, so we'll see how he does coming up the hill.
In any case, many thanks for the advice.
A second update: He made it up the hill coming back from school! Said that he stopped and walked it at one or two steep spots, but in general said the gearing worked for him. Now, to start working on the idea of bike touring ...
Last edited by Chinghis; 08-30-19 at 10:43 AM.