I don't know how to convince your parents, but both of ours sleep in our bed, and go nowhere near the furniture. We just tought them "NO" that they aren't allowed on the furniture. Nebo is a smart dog, he will get it. And change your sheets often, and use Febreeze or something if you have to--it should be no problem. I love having mine in the bed with me--such a happy little family we are, all snuggled up together. Kito comes over and curls up by my head, and Abbey usually ends up between us somehow, and she wakes us up with kisses.
Good Luck