What to do if my timid dog attacked another family dog?

I have a VERY timid 1 year old male (not fixed) Black lab X Boxer, and a 12 year old male (not fixed) mini american eskimo husky. They always get along well, and today I let them inside from the outdoors, they followed me into my living room, and they were walking between my couch and coffee table. There is a couple bones laying on the floor from them chewing on them last night. They have growled before by protecting their bones, but I turned my back for 2 seconds and all of a sudden I heard growling and whimpering at the same time. I turned around and my lab/boxer had my husky in his mouth, pinned to the floor. There was no warning growl or sound before the attack happened, I had no warning. The attack lasted maybe 10 seconds and now my husky has 4 puncture wounds on his chest, a slit on his throat on the underside, and a mive hemotoma bruise on the underneath of his chest. If everything does not drain properly in 48 hours he may have to go for surgery and get drainage tubes incerted. We have an appointment for a week from now for the spca to put down my lab/boxer, but is there something else I can do for him. I am leery of him in the house with my young kids as well. But I feel bad for having to in other words kill him.