Has anyone noticed an odd investment in fear with their skids? Has anyone had any luck addressing this issue?

Three days ago, I was watching Surf's Up with SS5. I said we should try to learn to surf someday because it looks like fun.

SS5: No. I'll never surf. I won't ever try it.

Me: You don't think it looks like fun?

SS5: No! I won't do it!

Me: Um . . . why not?

SS5: I don't want to get splashed by the water.

Me: So you'll never try . . . because of water? You play in pools, don't you? That water is the same as ocean water.

SS5: I'll NEVER EVER try to surf! Never!

At that point I gave up. But I have noticed this is a trend with both skids. They are extremely invested in being afraid of things and being able to refuse to do things. Up until about 6 months ago, SS5 was still afraid of trees. He still won't try to climb them. I'm not kidding. He is about to turn 6 and he has NEVER CLIMBED A TREE.

DH wants to take SS5 snowboarding this season, but I just don't see it happening. I feel like it is going to be a wasted trip because SS5 will get on the mountain, realize he's WAY out of control, throw a fit, and refuse to even try after the first couple falls. And DH and I will have spent our Christmas fund (we're thinking of doing a trip instead of presents) on gas and ski lift tickets to hang out with SS5 while he cries and is mad about not being in charge of the universe.

This sounds negative--and it is--but I really expect this is exactly what will happen unless we bring someone else to watch him when the much anticipated meltdown happens.

I love this kid, but his control issues drive me up the wall. BM has trained him to be upset about everything and anything he can't control, and so any event that is out of his usual is grounds for some sort of crazy meltdown.

Examples:
wind
rain
snow
cold
heat
new foods
people who won't do what he says
children who won't do what he says
dogs that are bigger than he is

How do you counteract this sort of pattern?