Congratulations on your new boy! And thank you so much for rescuing a mill dog, they are so deserving of a good life at whatever age they are released. Get him on some very high quality food and probiotics to help his digestion, as good grain free food may be the key to long life.
There are many youtube videos on training a deaf dog, this one might be a good starter:
https://www.youtube.com/watch?v=uUcWNnaoniw
Bless your heart, enjoy your new companion!