They will booby-trap the h*ll out of Mosul, and then probably 90% will pull out before surrounded. Then 10% will stay and fight to the death ala Stalingrad.
They’re going to drive slowly out of Mosul with all their weapons and child brides, and will be escorted all the way to Deir Ezzor in Syria by NATO forces.
Meanwhile the compliant media will tell stirring stories of the destruction of ISIS.