Good dog! But coyotes are usually half to one quarter the size of a wolf.
ETA - and I hate to be cynical (but I often am anyway) you are only hearing the owner's account of what happened, who incidentally is trying to raise money to pay the vet bills.
Right, or even 5 to 1, unless it was perhaps foxes or raccoons. No way a single GP is taking on a pack of wolves, very doubtful it would even be able win a 1 on 1 fight with a wolf. They are nice dogs and very good at warding off predators, but they aren't especially strong or athletic.