The late warmth in fall was rough on the arbs.  They need extra water when that happens to store moisture for the dormant period….most folks don’t think of watering in Oct. or Nov.  If they are totally brown then there is little hope.  If they are partially green, then pound some holes around them away from the trunks under the outer-most branch tips and fill the holes with Espoma, Tree-tone food.  If we have a dry summer, water extra.  If there is life to them, they will bounce back.