if my family was the first on the scene of a serious auto accident and the driver’s dog bit my son, who is responsible for paying his medical expenses?

The dog's owner is potentially liable IF he or she was "at fault" in some way--such as not restraining a dog known to be viscious or which was clearly in pain or frightened, so as to be more likely to bite. (There must be fault, or something the dog's owner did wrong, for liability in your state.) Auto insurance would not apply--a dog bite is not a car accident. Homeowner's might apply, but if the dog's owner and/or his insurer do not choose to honor your claim and voluntarily pay you, you would have to sue the dog's owner and prove fault to recover money. (At that point, if she/he has applicable insurance, the insurer would likely pay; but if not, the owner would have to pay her/himself.) As to whether you should seek pain and suffering, that depends on the severity of the injury and how long-lasting its affects are: generally, pain and suffering awards are only available for injuries causing long lastin and significant impairment to life functions or the enjoyment of life. Less severe injuries generally only get medical costs and direct out-of-pocket losses or costs (like lost wages, if someone missed work due to an injury).

The dog owner is liable for your son's injuries.  Although a duty of care is owed to rescuers, the auto insurance carrier may deny the claim because your son being bitten by the dog was unforeseeable.

If your son's claim is denied by the driver's auto insurance carrier, you will need to sue the driver for negligence.  Since your son is a minor, you will need to be appointed guardian ad litem to file a lawsuit on his behalf because a minor cannot file a lawsuit.  Negligence is the failure to exercise due care (that degree of care that a reasonable dog owner would have exercised under the same or similar circumstances to prevent foreseeable harm).  In addition to a cause of action (claim) of negligence against the driver for the dog bite injuries to your son, if the dog has a history of biting, an additional cause of action for strict liability should be included in your lawsuit.  Strict liability imposes liability whether or not due care was exercised and would be applicable in a dog bite claim only if the dog has bitten others in the past.  If this is the first incident of the dog biting someone, then you would only have a negligence claim and not a strict liability claim.

Prior to filing a lawsuit against the driver, obtain your son's medical bills and medical reports and file a personal injury claim with the driver's suto insurance carrier.  Compensation for the medical bills is straight reimbursement.  The medical reports will document the nature and extent of your son's injuries and will be used to determine compensation for pain and suffering, which is an amount in addition to the medical bills.  If the claim is denied by the insurance company, proceed with the lawsuit for negligence (and strict liability if applicable) against the driver as discussed above.  If the claim is not denied by the insurance company which is unlikely and is settled with the insurance carrier, NO lawsuit is filed.  If the claim is not denied by the insurance company, but you are dissatisfied with settlement offers from the insurance company, reject the settlement offers and file the lawsuit for negligence (and strict liability if applicable) against the driver as discussed above.

If the case is NOT settled with the driver's insurance carrier, the lawsuit for negligence (and strict liability if applicable) on behalf of your son must be filed prior to the expiration of the applicable statute of limitations or your son will lose his rights forever in the matter.