That’s a really tough situation. As a parent, I personally really enjoy the game (having played Magic off and on in high school and college), so it was easy for me to get on-board with Pokemon TCG. The thing I tell parents at my league is that Pokemon is a excellent tool to teach math skills, critical thinking and sportsmanship. Those are traits any parent can support, but even then, some can’t get past the fact that its a “cartoon” and “childish.”
As for travelling to events like Regionals, a lot of burden falls on the parent typically (hotel, getting there and back, sitting around being bored during the tournament). On the prize size, The top 64 juniors get some sort of pack prizing, (1 box for top 32, 1/2 box 33-64), which is nice since Regionals never hit 64 juniors, so everyone gets something.
If your brother can make World’s, you may want to work on convincing your parents to take you World’s in Memphis, if that’s the 1 trip they’d support.