Vehicular manslaughter requires proof of gross negligence by the driver. That's a tough standard that goes far beyond bad driving (it essentially requires a knowing disregard for a risk to human life). While we certainly don't know all of the facts, I'm skeptical that gross negligence could be shown in this case.
That stinks and is one reason why I am glad that we have no other pools near us. Little risk of kids being poached or heading to a different pool. (On the flip side, we have a significant waitlist, so hard to bring in new kids.)
Corrected to reflect Weenie Rule #17: No one should care what the GFS says beyond 3 days unless it shows snow. If it doesn't show snow, wait for the GEFS.