there is nothing in your description that indicates that there may be any criminal liability involved. Everyone has a duty to maintain control of their vehicle, but when someone's failure to do so results in another person's injury, it is deemed negligent--not criminal. Thus, there is no jail time involved.
However, the injured parties can recover for the injuries caused by the negligence. Recovery may be awarded from the driver, the vehicle owner, or both. This is accomplished through a lawsuit.
The first line of defense is your auto-insurance. To the extent that your insurance will not cover the cost of injuries, the responsibility falls on the driver and the owner. The injuried parties can recover against some of your assets, but not all of them (such as pensions and 401[k]s). I oftentimes tell clients that they can't get blood from a turnip.
If the owner and/or driver could not afford to pay a civil judgment, they could discharge the judgment in bankruptcy.
Let me know if I may be of further assistance. Thank you.