Coincidentally, I broke out one of my upper front teeth and cracked a few others while I had braces on, similar to your son.
The dentist was pretty pumped that I had braces at the time of the crash because the braces apparently spared my teeth from some additional destruction. At the time, none of my teeth were completely broken out, just cracked at the roots and knocked crooked in my mouth. Because of the braces functioning just as braces are supposed to, the teeth were gradually straightened back out over the the next week-or so. Besides being weak, my front tooth, as well as some others, were otherwise fine.
However, at college the following year after my braces had been removed, I was involved in a bit of fisticuffs that resulted in my front tooth finally being broken all of the way out. Due to how the tooth broke out, cadaver chips were required to be stuffed up into the roof of my mouth to form a more solid structure before an implant could be added.
Between the time when the cadaver bones were packed into my gum, and the time when the implant was eventually installed, I had two "placeholders." The first placeholder involved the dentist literally gluing my front tooth into my mouth, attaching it to the two teeth around it. This was a decent temporary solution except that, if you examined the front teeth closely it looked kind of goofy, and it eventually broke out while eating... The second and last-resort placeholder was a "flipper."
To try and fix my grill after the glued in tooth had broken out, I first tried the flipper, but I literally couldn't talk because the retainer was so large and cumbersome in my mouth. To solve the problem of the broken out glued in tooth, and a flipper that wouldn't allow me to speak properly, I purchased myself a Dremil tool to reshape the tooth and literally superglue it back in. This was a solution that would last for about a day, and then it would bust out and I'd have to again re-glue the tooth back in my head (literally "rinse and repeat"). It got to the point where I would carry super glue with me at all times, and I had a Dremil living on the bathroom counter next to my toothbrush.
Also, during this same time period, I was working as a "hasher" (see: dishwasher") at a girl's sorority house. It was an INCREDIBLE gig with some ridiculous fringe benefits. However, juggling that particular job, while at the same time making sure my tooth was glued into my face each night before work, was kind of a challenge.
After farting around performing cosmetic dental surgery on myself most mornings, I decided to try my hand at Dremil shaping the flipper to allow it to fit more properly. After I did some significant grinding on the structure, I was able to learn to speak around the thing, and the modified flipper became the final solution before the implant could be fully installed. The added benefit of using a flipper is that I could randomly pop it out mid conversation and jack with people, and I could take awesome pictures. Check out my license photo from that time:

Eventually, the cadaver bone chips heald, and the implant was installed. No huge complaints with the implant and it's been over a decade. The only issue I have is that my gum line isn't exactly straight above my top teeth. Fortunately I don't have a "gummy" smile so this isn't really noticeable.
Best of luck to you and your son! This was a challenging ordeal for me but in hindsight (and because I've had no further problems with my implant) it really wasn't that big of deal at all. It was a financial hit for sure, but none of us got involved in this sport because it was cheap (or safe).