I hope I can still bike tour when I'm that age. That's awesome. Are they camping too, or just staying with hosts or hotel? They're certainly fully loaded, so I assume camping gear?
And why not on an e-bike? It's all of the great parts of riding a bike, none of the less enjoyable stuff like pressing your worn out legs up a long, steep hill or that last crappy 5-10 miles after you're tired and not to the camp ground yet. I haven't toured on an e-bike, but I bet it's pretty great.