I understand your reluctance to surgery for your son, as a mother. As someone who suffered numerous ear infections as a kid I know what he's going through.
Ear infections can be excrutiatingly painful AND emotionally traumatizing if they recur so often. I have vivid memories of being a child and suffering in pain.
I had my first set of tubes put in when I was about a year old and had them re-installed (for lack of a better term) every six months until I was seven, when they finally took out my adanoids. (that's 13 sets of tubes!!!) I've continued to have "ear issues" but they are to a FAR lessor degree! Now it's more of a paranoia when I get water in my ear or feel a cold coming on... But that's the "emotionally traumatizing" part I was referring to.
I was speech delayed due to the hearing loss and also have lots of painful memories of my big brother having to "interpret" for me because he was the only one who could understand what I said!!!
The bottom line is this...
The ear surgery is absolutely painless as I recall. Get that Curious George book, "George goes to the Hospital" :) You don't even stay over night for tubes!
Having my adanoids out hurt a little, but I hardly remember the whole thing. I remember having ice cream and my mom stayed with me in the hospital overnight.
Also, speaking as someone who later went into the field of deafness/hearing...having fluid in the middle ear, repeatedly and/or for long periods of time, damage those three very important, little bones by eating away at them.
Just a thought.(do the surgery!)