I found that when I would lay down on the floor and be quiet the traumatized dogs I had as fosters, or kept in the case of Petey would feel more comfortable. There is something to be said for gaining trust by getting down on their level. It took a few days but soon I could just sit right next them and the next step was touching them without picking them up. If they can stay on their own four feet or laying down, sometimes they feel less " threatened" and overwhelmed. Slow and quietly you will gain his trust, I have faith.