I'm not sure, actually and I'd hate to guess. I asked my husband, but he doesn't remember what the doctor said (if the doctor even specified). He does have a pending appointment with an ENT, but couldn't get in for a few weeks. That's a bit frustrating as ear infections can get pretty nasty. I'd hate for his problem to become worse just waiting to see a doctor. Still, I'm glad for this because maybe the ENT will have better insight as to what the real root cause is. This morning my husband did say that he feels like there is water trapped in the ear and that he had some drainage this morning. That seems odd to me. I do wonder if some of this is allergy related. It's been a bad year here for allergens. Hopefully the doctor can address that as well since it can take 4-6 months to get into an allergist in our area.
It would make a big difference as to the recommendations as @John C. Ratliff pointed out above. Even visible drainage doesn't tell you for sure, because that can come from a severe middle ear infection that causes the tympanic membrane to rupture. Either way though, he should not dive until this clears up. Doing so could aggravate it further.
Best regards,
DDM