Dads are like that. They want to be able to fix everything and become frustrated when there's no solution.

You mentioned you don't feel you need your dad's support, so it's okay if he doesn't understand. However, if you want to help him understand (because he does love you and his reaction is probably more because he hates what's going on and that he can't fix it), then you can write him a letter or try to find another way to explain it to him like giving him some research sources that support your point.

I'm sorry you have to go through this. It's not a pleasant battle.