I realized that it would be helpful, to those of you who might have books to recommend, to describe why I thought time travel would be an enticing subject.
Incident 1: A couple of weekends ago, Archer fell and got a bad rug burn on his arm. He refused all medical attention but seemed distressed. A few minutes after the event he came up to us with tears in his eyes and a quaver in his voice. "If only I could travel through time, everything would be all right," he managed.
Incident 2: During the tornado outbreak last weekend, we had to go to the bathroom (our safe room) when a funnel started forming near our location. I had the Weather Channel radar on my laptop, and we were watching the time-lapse "weather in motion" view. Archer was fascinated by the timestamps on radar images, especially noting the fact that the latest one -- the "right now" image -- was actually five to ten minutes old. After the danger had passed, when I was tucking him into bed, he said with a delighted smile on his face: "It's like the radar was taking us back in time."
I'm sure there are lots of books where time travel is a mechanism to get some kind of plot going about history or whatever. Are there books he might like, similar to A Wrinkle In Time, where the nature of time and the consequences of moving through it in an unorthodox way are major themes?