He probably wouldn't do to good especially if you have never had a dog in the house before. I''ve never heard that Bichons love white animals, I think that is a superstision. I don't think your cat will do too good. He will not like it to much.
if the cat has never been around dogs it is going to be very stressed out with a puppy coming home. 21 years is pretty ancient for a cat. thats like having your 95 yr. old grandma watching your 2 yar old child. good luck!!!
Before My Sweety was pts she was 20 and i had Storm (a puppy at the time). Let me tell you Sweety had always been around dogs but she did not like the fact that there was a puppy poor poor Storm got beat up all the time just trying to be friends. Finally i had to keep them in different rooms. Old cats and puppies i wouldn't advise to anyone after what i went threw.
Dear Bichonluver5, He probably wont do too good, because of him age. It is just a myth that Bichons love white animals. I am pretty sure your cat will not do good. I would wait if I was you. Best of wishes, LindyLou