Maybe he had a rear brake caliper that just would not stop dragging and needed repair every 2 minutes? Maybe he needed a fresh bottle every 30 seconds and each hand off took 20 seconds a la Floyd and Morzine?
Regardless, IF, and that is certainly an IF, he was hanging on or taking advantage and getting towed, that is really unfair to the others that actually pedaled up the hill.
It seems unlikely that a couple of guys, who clearly do not have the star status that Cav has, would make up a rather serious accusation like that. Not impossible, just unlikely, which imo would tend to make me believe it. The guys all get a little help on each bottle hand out, on each bike swap or puncture, so know the gig. To actually accuse someone of it would seem to have implied that the assistance was a little more egregious.