KYC can be asked for all sorts of reasons, we don't need to violate ToS to be asked for verification! Simple moving funds too fast you touch the AML policy and you can be asked for KYC! Anyway, it's not a big deal if someone is honest!
It's possible that he has made a mistake/violated part of the TOS so some accounts have to verify KYC early due to his alleged abuse or suspected account, but whatever the speculation of the main cause we should review the TOS again because he should have completed the KYC before making any withdrawals.