If your school is a reputable outfit and not a "pilot-mill" for foreigners and they have a clean record and good reputation with FSDO and ATC, I believe, especially being a 141 that once assured there's a process in place to prevent an re-occurrence, this situation is over. Now if there's more to the details or the school has a bad rep or FSDO has already gotten many calls from ATC on the students, all bets are off. If it does hit the fan, with 141's, it usually management who takes the hit and that's the purpose of a 141 is to have oversight of the CFI's who have oversight of the students. Management will usually sacrifice a CFI rather than lose students or a 141 certificate as their "solution". It looks good on paper to say we eliminated the problem even though he might not be the problem, and the FAA has no say in the matter as they took corrective action even if we think otherwise, unless it happens again. If your comfortable with your situation with the CP, I think you can stop worrying.