It would be a problem if someone did that themselves without the support team knowing about it. As @Text mentioned it, the support agent have told him that they are going to manually update the information for his account which means they are going to change the country from Hong Kong to Philippines and then the user can do KYC without any problems if asked.
I knew, but I recommended him to ask for one more support from MonkeyTilt team, by leaving a note, for example internal note, on his account. It's not impossible that they manually changed nationality for him, but forgot to leave an internal note, and if their system did not automatically note it, his account has risk of problem in future.
It's not big concern now, but make sure of going to ask the team for a note, that will keep his account safely in future, and he will no longer have to worry about it.