While I also agree that prison often inflicts significant damage on inmates, the sole question here is not what's best for the perpetrator. There is also the issue of deterrence that the criminal justice system has to be concerned with. That's one of the challenges to recommending particular sentences. It's a tricky balance.
The mom in me absolutely hopes there is significant consideration given to his youth and absence of criminal record. At the same time, it's hard to see how anything other than a prison sentence would send the right message to others about the seriousness of the crime.
If it were my kid, I'd absolutely want him to have a good lawyer who will fight for leniency. I'd want him to know I love him still, and have hope for him. But I'd also be trying to help him understand why he's in this jam and to accept the consequences with courage and a determination to change the course of his life.