Happy birthday Karen,  Your dog is beautiful.  Have you ever heard of Ashwagandha?  It is an herb of east "Indian" herbal medicine.  It helps repair nerve tissue.  You might research it on www.lef.org and see what you think.  It doesn't cost much and you could try it for him.  The kind that says Sensoril has been used in human and is processed in a manner that is beneficial.