Thank you all for your responses! He is neutered and we've been keeping a close eye on him and my son together. We have another 4 yr old son who he's had NO issues with, even in the same exact situations. (For example, my 4 yr old can stick his hands in Trooper's bowl and not be growled at.) We've also made sure to feed Trooper only after everyone else has eaten to really drive home the fact that we are the alphas and he is not. My husband had given up on him and wants to find him a new home- I'm committed to fixing the issue, but also not willing to risk my son's well being. And honestly, keeping an eye on them 24/7 is stressing me out