Hi pixiestudio,
Since your question is about how the dog will respond to the loss of hearing I think I can help you in finding the answer as my dog lost not only hearing, but had one eye taken out and was blind in the other. While I was a nervous wreck at the time of the eye operation , he came home acting fine and like nothing had happened.
His sense of smell was heightened as he could smell a biscuit a mile away! Really, we do put too many of our emotions onto our pets. My dog still played as normal, and still got grumpy as normal.
You will have to make adjustments , like leash walking or staying with him as he goes out for potty so you know where he is as he is not going to be able to hear you calling.
Put a reflective collar on him so he is easy to find at night. Stomp your foot on the floor to get his attention inside as he will feel vibrations if he is not directly looking at you. My dog I found, knew my routine better then I as in the morning he would know I was in the room (if he was sleeping) by the smell of my coffee.
So don't put yourself through a lot of torment. I have helped train many deaf dogs and although they are not allowed any more to become Therapy dogs , they are the dogs that really excel at training because they always watch the owner.
dog training consultant
24 years training & behavior,pet first aide, Therapy dog eval., PA Animal Response Team