Hi Jen, sorry you are having so many problems with Ralphie, and some of them very serious.

The safety of your children is of paramount importance, the fact that he regularly bares his teeth and growls at your children is a major concern, these are warning signs, a bite may follow.

At the moment you are responsible for this dog, I know you didn't cause his problems, but he should not be off lead in a public place if he shows aggression to people.

As regards changing his behaviour he is not too old, I don't know what behaviourist you saw or what advice was given, or whether you followed it, did they do any follow up rehabilitation work with Ralphie, or were you just sent away with a written program to follow ?

As for would he be better off with a more experienced owner, possibly, but to be honest people are not queued up to take on a people aggressive dog.

You've got a difficult decision to make here, I don't envy you.