I think that what your brother did is a rite of passage when a young guy gets a 4x4. My brother got a nice new Toyota 4x4 way back in '81. The second day he had it he did something very similar to what your brother did. My parents and I were driving home past a huge construction site. We saw a Toyota pickup that looked like my brother's. It just happened to have its front end buried in a huge pool of water. There was a tow truck hooked up to the back end. We stopped, looked, and drove off. My dad was just shaking his head.
My genius brother did the same thing your bro did by underestimating what he thought was a puddle. Luckily for both of them they didn't decide to do an Ivan "The Ironman" Stewart jump and sink the whole truck.
I got a 4Runner in '88 and learned from my brother's mistake. I used to go running through mud fields but never got it stuck.