Yes you can communicate via email but it’s very rare for current casino that accepts KYC documents via email since this should be handle by services that allows to do KYC because it requires handling of important information while it requires different license to process KYC.
I guess that's what he had mentioned, he go through the kyc link provided by the support he/she communicated via email. Because submitting personal info for kyc via email attachment is very risky in anyways.