i know the feeling christine. my grandmother is 86 and was told she had to go into hospital for a number of reasons but she refused point blank. We did eventually get her in and she was so ill at this point that she couldnt say or do anything she was so weak, but all she did when she got there was moan and bitch and hurl abuse at the doctors and nurses that to be honest they must of been glad to see the back of her.
your grandfather is probably scared, like many of older peoples attitudes are, when you go into hospital at that age, you dont come back home. Have you had a chat to the doctor, perhaps they can do treatment from home by having a nurse coming around? good luck xxx