That sucks. Give it time. Hopefully he'll get over it.
Luckily I've never had to deal with this with any of my kids. They've all been around snakes from the day they were born and don't look at them any different than they would a dog, cat, or fish.
I have to be honest, this made me laugh a little. But I agree. Usually after someone takes a bite or two they aren't worried about it anymore. My wife has actually been talking about intentionally getting bitten by some of the balls so she can get used to it and gain the confidence to handle some of the more temperamental species, like bloods.