There are a few things that will help this:
SURGICAL AS FOLLOWS-
1) Deviated septum surgery
2) Nasal valve surgery
3) Polyp removal surgery
4) Tonsil removal surgery (the eustachian tubes sit right behind the tonsils, so removing tonsils often helps widen these tubes)
NON-SURGICAL MEDICAL SOLUTIONS AS FOLLOWS (sometimes these dont work and you need surgery though):
1) Allergy shots (reduced allergies = less inflammation = less closed ears, nose and throat)
2) Corticosteroid nasal spray
3) Corticosteroid ear drops
4) Allergy medicine like benadryl or claritin
5) short term, advil will help to reduce swelling and minimize damage
METHODS IN THE WATER: (These are useful regardless of your medical situation)
1) Swallowing and then moving your jaw in a circular loose motion, including up and down, left and right
2) Gently blowing while closing nose (valsalva)
3) gently blowing nose with it open
4) swallowing in general
5) Make sure you descend and ascend VERY SLOWLY
6) Try to equalize every foot or two, for the first 10 meters down, and every 2-3 feet after that
7) Descend and ascend headfirst (upright position, head up, feet down), as you equalize easier that way. (Yeah I know, it looks much cooler to have proper trim, but taking care of your body should be priority #1 here)
I don't think there's currently surgery to widen the eustachian tubes/ear canals themselves, though. But surgical methods 1 thru 4 are all very helpful in general. I've had all of them done except the nasal valve surgery (which I still need to do) but I am equalizing much better now overall with those things done. It's really night and day! Also, allergy shots are an amazing lifesaver for people with allergies. They will help you tremendously, especially if you go 2x a week for the first 2 months, and really build up your maintenance levels quickly