Race tracks are 100x safer than public roads. If he's going to crash, it's better to crash on a race track.
of course it is, but it only takes one time for something major to happen, and he's had 3 accidents in 3 races...i'm not familiar with the type of racing (or the track layout) being done here, but if he wiped out and another bike hit him/ran over him, that could cause serious injuries...perhaps he slides into something else (wall, embankment, another bike, etc)...even just catching some ground at a weird angle could result in a serious injury.
sorry if i'm concerned about a "friend" (online) whom i've come to know over the years...if we were all 18 and indestructible, it likely wouldn't be a concern, but we're all married now, with loved ones at home and financial obligations to provide for our family...i would just hate to see something bad happen...as i said, if he were doing it for 5 years and this was the first time, it likely wouldn't be a concern, but 3 for 3...come on now.