He needs a zero account balance and he needs to cancel all of his subscriptions. If he has cancelled all subscriptions, but some haven’t expired, contact iTunes Support. He needs a credit card issued by a bank in the country the store is in, and he needs a billing address in that country. If he has an account balance, either buy something more expensive and pay the balance with a credit card or contact iTunes Support and ask them to zero balance his account.
Purchases - View, change, or cancel your subscriptions. https://support.apple.com/en-us/HT202039
Purchases - Subscriptions not billed through Apple https://support.apple.com/en-gb/HT207865
Region - Change your iTunes Store, iBooks Store, or App Store country or region. https://support.apple.com/en-us/HT201389
If necessary, contact iTunes Support. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.
iTunes Store - Contact Us - Official Apple Support. https://support.apple.com/en-euro/itunes-contact
iTunes Support – world wide https://support.apple.com/choose-country-region/itunes