Cauliflower ear could be caused by an ear infection, mites, or other parasites. Frankly, I have no idea how that medicine would react with your dog, what side effects it would have, especially if it is geared towards humans, so I would not use it.
What I would do is put colloidal silver and tea tree oil in the dog's ears. Massage it tenderly and then make sure to get the liquid out. Am I to understand that he has hematomas in both ears? If hematomas are present, you may need to see a vet. Sometimes surgery is necessary. However, before using any antibiotics, I would rely on colloidal silver.