Rearended - can I have a claim against the last car that hit a car that hit me again?

3 cars hit my son. Vehicle 1 hit first and thenmoved to the side of highway. Vehicle 2 slammed into my son and subsequently, vehicle 3 hit vehicle 2 which caused vehicle 2 to slam into my son at over 55 mph. Vehicle 2 uninsured. Vehicle 3 insured. All received ticketed EXCEPT my son. What claims can I get if Vehicle 1 insurance doesn't pay all. Or even if Vehicle 1 pays.