Un-Socialized dog - Training?

You were bitten several times by this dog and YOU feel bad that you don't want to spend time there?!!! You need to tell these people what happened (if they don't already know). They need to bring the dog to a vet to make sure the dog doesn't have anything physically wrong with it and to discuss its behavioral problems. The vet can recommend what steps to take next and have their dog trained. At the very least have it muzzled before it bites someone VERY seriously and they have the dog taken away from them (maybe that what they really want!) Its not your job to get your friends dog to like you, the dog has much bigger problems then that. I wouldn't bring any animal of mine to their house either. And the dog has also bitten a 4yr. old, their sisters and them? What the heck are they waiting for???