Wolves leave their packs at two years in the wild. There would be time for wandering, being accepted (this takes several months) and finally reaching a highspot (this could take up to 10 years, if the Alpha is still young). Then there would be the death of the last alpha (up to 5 years) and by this point, he would be dead. You could put that the last Beta died, he was made the New beta, and then that the Alpha was killed.
My analisys is compleate XD