I found the D4 to be one of the strongest cars available. I had a massive amount of confidence in it and as a result I found I was faster. The strength of the car was tested on many occasions and as I mentioned before, it never missed a beat.
Bangersonacid, what motor and battery combo is your brother using? If you give a novice driver a fast brushless and Li-Po batteries, you are asking for breakages. Perhaps try fitting a 19t or brushless equivalent to see if the crashes stop.
