I am looking for a website where I can buy cryptocurrencies using a bank card (debit card). It is important that the platform accepts users from sanctioned countries such as Libya and Syria.
I think you're going to find it rather difficult if not impossible, unless you find such a service in those specific countries. Any bank card processing service in the US (and likely Europe) will flag the transactions and prevent the vendor from receiving the funds. If the tranches are large (over $600,) they'll also get flagged for potential fraud, and cause the vendor all kinds of trouble.
Have you tried Bisq?
He won't find a Bisq peer that accepts bank cards, that's not a payment type provided for by Bisq1. Even if he was able to (somehow,) or use Bisq2 he's only going to run into the issue I pointed out above.