He's not aggressive. It has nothing to do with dominance, his past, being neutered ect. He's a husky. Prey drive is expected in the breed--small dogs, cats, squirrels, birds...they all look the same to a husky! If it's smaller than them, it's prey and they will hunt it! Prey drive can be controlled. It can't be eliminated.

This is the owner's fault...not the dog's. They are in the wrong--the dog was off their property, unrestrained and killed a dog in his own yard. That husky should have never been off his owner's property unsupervised. The neighbor has grounds to cause all sorts of trouble---legal, with animal control ect. Your friend needs to apologize in a HUGE way to the neighbor. Pay for a new puppy when they are ready. Do whatever it takes to prevent a lawsuit.

Then they need to ensure this never happens again! They need to make their yard escape proof. If he was chained, that needs to stop immediately. He needs a fence--a minimum of a six foot high fence secured at the bottom to prevent digging, one that can't be climbed. Nothing near it, no weak spots. It will need to be checked daily! It takes a split second for a husky to find an escape route.