Also, that their precalculus course did not cover the material sufficiently well for him to place into calculus.
If he took calculus in high school, earned a good grade, but failed the AP test (presumed, since he had to take a placement test and was placed into precalculus), that is another bad sign about the high school’s math courses.
That he failed precalculus the first time might even suggest that the lower level high school math courses (algebra 1, geometry, algebra 2) were of low quality. Perhaps he knew that material just well enough to pass those parts of the placement test, but not well enough to use it when applied to problems in higher level math courses.