Can we get medical compensation for our son's injuries?

I am a lawyer in CT and practice in this area of the law.  You should go after the homeowner that permitted the fight to go on, the school, and the kid that hit your son.  The more parties in the case the better for settlement purposes.  You need to get a lawyer involved  asap.  As far as liability is concerned you want to get an insurance policy for compensation.  The school's liability is questionable as they may be immune from liability unless the fight was foreseeable.  the homeowner is likely not liable unless they knew about the fight and let it go on.  Thus, the kid's parents of the kid that hurt your son, and the kid himself are the most culpable.  They should have the means to pay for your son's injuries.  Again, make sure you hire a lawyer ASAP.