What is the issue with phone number or nationality. Are you not able to see your nationality in there registration portal or is the phone number you have not corresponding?
I think he didn’t change his nationality or the casino auto assigned it upon registration. Some casino automatically assign country since they don’t require KYC level 1 such as providing mobile number and country during the registration.
Actually, most of my KYC info during the registration process is always use Afghanistan. Anyway he can’t do the KYC if his phone number and country registered on his information page is different to his original country ID.
The support might probably not fixing his details properly.