Hi , I'm James DVM MRCVS and would like to help you with your question
Sorry to hear about Barney .
By the sound of it it could be one of two things - either he has indeed an ear infection or he has something stuck up his ear canal (like a foxtail or other type of seed) .
What best be done is to have a look up the ear canal first (done by your vet) in order to eliminate the option of a foreign body being stuck and as well to asses what is the leading cause of the infection if it's not the former.
this can be done by preparing a smear of the waxy material in the ear and looking under a microscope .
According to the results - your vet will then determine which is the best course of treatment (antibiotic / ear wash ect.)
I hope this helps .
If you have any further questions - please let me know.
all the best