Wouldn't it be better to give them clear problem sets which might be occasionally challenging but that they can still solve on their own? Shouldn't school be about giving kids tools that they can use themselves?
We had a similar bad experience with a Harkness method precalculus class for my older son at a different boarding school. He struggled all year with the "figure it out yourself" methodology. He is very strong in math and went on to all 5s on the Calc AB, Calc BC, and Stats AP exams after classes with traditional instruction.