Yesterday I had a group lesson that had been taught by him the previous day, the class was wedge christying but with a fair amount of upper body rotation and with their weight a bit back. After a warm up I start off by trying to get them to feel the front of their boots. After a few exercises and half a run, they start to look a bit more centred, one of the class then asks why T (the other instructor) told them to sit down and feel the back of their boots. I was pretty dumbfounded, normally I play off different instructional techniques as a difference in style (where I teach has people trained from all around the world), but this was the opposite of what I was saying, so I just told them T was wrong, maybe I should have been more tactful, but he really messed these peoples skiing up. There were a few other instances in the lesson where what I said prompted a 'that's not what T said', at the end of the lesson the class were very happy with the lesson.
Today I am on privates, I think he is back with this group, if it was up to me he'd be on the beginner slopes until he made an effort to ski and teach something resembling what everyone else teaches, but it's not up to me. What should I do?