The true disadvantage of using a VPN is that if the casino catches you, your funds are going to get confiscated and then you will also be ask to submit your KYC. We shouldn't only turn off our VPN but we need to uninstall it for our own safety. I am sure that there are still casinos out there that are fully legal in our country.
If his location is included in the list of prohibited countries in the TOS then it is not recommended to use VPN access because if the casino asks for KYC it will not be accepted, so the account cannot make withdrawals or even the account can be frozen. He needs to weigh the risks before accessing an online casino using a VPN. Like your suggestion above, he may find alternative casinos that are legal and accessible without any prohibition rules.