Most likely you know all the steps for desensitizing him. I pray those will help.

Another option (besides clomicalm) are Composure Chews.
http://www.vetriscience.com/composur...dogs-MD-LD.php

More info here:
http://www.vetriscience.com/sellshee...re%20Chews.pdf

I use these for Tasha and Marlin for grooming here at home as well as for visits to the groomer. Tasha needs 1, Marlin needs 2. These DO help them.

Prayers that dear Snoopy learns to trust that you will return to him!