Then yeah, the waiting on the vet sucks but is the best plan. He may need an anti-nausea med. Call them if the email hasn’t been answered by a reasonable time (say after 4-6 hours of their posted opening time today.) Emails are less time sensitive than a phone call.
Food can be swapped or supplemented with plain baked or boiled chicken, rice, and puréed pumpkin (NOT pie filling!) if they’ll take it.
When I clear a few time-sensitive projects, a Jellyfin deep dive is probably in the works.