What crap!
Any half-decent school should ensure that their student records are sufficiently good that any other instructor can carry on after your friend's instructor leaves, with very little impact on his training.
My PPL instructor was offered an airline job when I had around 40 hours. He spoke to the CFI to try to arrange to continue to work part-time until some of his nearly-finished students (including me) had their licenses, but this didn't work out, and the school found me another instructor. This had absolutely no impact on my training whatsoever, and any school which can't do the same should be avoided.
FFF
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