Omg he is GORGEOUS. And you were concerned about his size? He's beautiful! Great sized Frenchie!
A deaf dog...interesting! My professional career is based on working with deaf people, but to train a deaf dog...very interesting! You'd just have to be in his line of sight to get his attention, I suppose, as he couldn't hear your call, etc. (Just thinking out loud here) Many deaf people I know have dogs (that can hear), but obviously the dogs understand sign language, so it can be done!
Bulldogs are also at the bottom of the list as far as who is easiest to train, so don't blame yourself. You're dealing with a hearing loss PLUS a stubborn breed.

(Although I think Frenchies are pretty intelligent, no matter what the experts say)
Titan is a SUPER cool looking dog. Love his eyes! I hope he's feeling better with his giardia. Crazy how stubborn it's been, eh? Poor baby...