Basically it depends in several things.
1. Most States have nofault so your friends own auto policy fir that car would cover medical bills
2. They can find out the coverage of the other car by contacting that drivers ins company or having a lawyer do it. Usually hiring a lawyer is the best bet and they work on contingency
3 do your friends have underinsured on their vehicle...it is to protect you from being hit by someone with a small policy