not necessarily, it really depends on how elevated his heart rate is, and in turn how physically demanding the rides are. if he rides in the 80-85% range on every ride, he's not burning fat, he's burning light muscle mass. if he rides in the 70-75% range on a consistent basis, even if it's only for 1 hour say 3 weekdays a week, he will burn more fat in those 3 1-hour rides than he will on his 100+ mile weekends where he's pushing himself to his max.

and sure, there are probably people that will argue that, but that's what i learned from first hand experience. most of which was on a spin bike, for only 1 hour at a time, 2 or 3 days a week...