Hmmmm. Here's the reference for one of the charges
Manslaughter, Article 119 in the UCMJ. The maximum punishment for Involuntary Manslaughter is dishonorable discharge, forfeiture of all pay and allowances, and confinement for 10 years. I have no idea if the 10 years is per person or per incident.
This compares to Max. confinement of 3 years for Negligent Homicide as "recommended:" for SSGT. Frank Wuterich after his hearing. Again, no clue if this is per person or incident.