Without knowing his training plan, I wouldn't assume anything. When I ride by myself, I would appear to have pretty random speed also. I pick all kinds of weird things to use as interval markers. If he's used to a much warmer climate and is visiting for the weekend, 60 could feel cold. At 60 I'd have on knee warmers or tights and a long sleeve jersey at a minimum. And if his hands are sensitive to cold who knows what he was trying to do. Just say hi and pedal on your own pace.

Trek, the passing thing -- I do it also if another cyclist is the "weird thing" I've picked out as my marker. I do usually try to say something nice as I pass so that I don't offend and they know what I'm doing.