In Of Mice and Men, what are similarities between Candy and his dog?

The dog used to be an amazing dog and was known as being a great sheepherding dog. Candy used to be very talented as a farm hand and with the animals. But, both dog and man are aged and fast becoming useless. Candy can't (and won't) put down the dog and he's afraid to stand up for the dog just as he's afraid to stand up for himself. Both are a sad pair.