I've had large breed dogs for 15+ years, mostly pits. Zero hesitation to get rid of one of them if they show any signs of aggression towards people, especially children. I've only ever had one that we had to get rid of and it was a Rottweiler that had anxiety and fear based issues since it was a puppy. Eventually as an adult it turned to reclusive and aggressive behavior. I understand their hesitation, yes they're family, but at the end of the day they're animals capable of inflicting severe permanent damage and death. You have to respect that. You cannot take any chances, and that dog should be taken far away from that kid and probably any kids