If this is not the first time they've had a dog that's had to be put down for behavioral problems...it should be obvious to them that they need to take a step back and learn how to raise a dog. The saddest thing about it that the dog and the dogs in the past will or already have paid with their life for the lack of discipline and absence of training their owners have failed to provide them with.

From what you've said... I can only assume the bites have not been too serious. Your friend needs to realize that all it would take is one bite with the wrong person and she can be sued and could lose everything, not just the dog!!

Find names of animal behaviorist in her area, and HAND them to her. Don't rely on her to look up names and phone numbers. Let her know that you are serious and you #1 don't want anyone to be bitten again #2 worry about what could happen next time. Let her know that you're looking out for her own good as well as your own and your son's!!!