I'm sorry, too. Fish can be so frustrating and no one seems to know much about them - although I did meet a vet once from NC who saw fish for $100 a visit (I'm sure he's upped that by now).
My daughter had a frontosa that got sick and I did everything I could for it - read up on it in every book I could get my hands on, talked to all kinds of dr's, etc., only to end up having to euthanize. Sent it in for necropsy with a very detailed explanation of what had happened, what I had done, etc. Know what I got back? Just about word for word what I had told them.
Hope the rest of his fish are okay and showing no signs of problems - he should probably still go through the testing of water, etc., that was suggested just to be on the safe side.