This is just my belief so please ignore if you want.

I believe in grace. So that means that no matter what we do (and we all do stupid or wrong things) if we acknowledge that God gives us grace and forgives us.

The illness is something that just is. Asking why me versus others doesn't really work because the answer is why not me?

But it is not punishment. God knew what he was doing when he made us with this glitch in our brains. Good things can come from it too. It just takes great patience to see them.