Oooh, didn't think about that point! Had the child died in the fire truck en route, that would have been a nasty lawsuit.
Not knowing the exact situation generally a seizure is not a life threat. Young children have febrile seizures when they run a temperature which you treat with cold packs and keep the airway open. Scary yes, fatal, no.
In PA where I live you have to be an EMT to give a patient O2 so they may be in trouble for that also. This is not a problem with the fire department, it’s a problem with the regional EMS council. It’s called practicing medicine without a license.