Golden ret lab and chow mix?

my mix breed dog he hurt our 2 1/2 yr old on the chin and i called the pediatricians office to find out what i should do they said his tetanus is good for 5yrs and i was glad about that and when heard my toddler cry i knew something had happened and i heard the dog with this sound from him as if he did something to our toddler and my husband came down and went after the dog and put the muzzle on him and we use the muzzle for excessive barking cause we have been warned by the dog warden and if the dog gets another complaint of barking they will come to our home and will euthanize the dog so now we are going to give him up and our oldest who is 16 says that this is his dog and we are not going to get rid of him and he don't understand that the dog does those things cause of his little brother pulls on the dogs tail Alot and he is 2 and a half kids do those things when they are little and the dog should not growl at the baby for pulling the tail and being that the dog has chow and those types of dogs are not kid friendly at all and the dog does need room to run and he is walked