Why do both pups need to go to the same home? Sound suspicious.
I don't really think it's suspicious for them to want both pups to go to the same home, since they are brother and sister and have already bonded together. If I had to pups that loved each other and for some reason had to rehome them, I would want them to get to stay together too.
Great danes? They're so young I wonder how bonded they are. I would think with a dog that potentially-large, having them go to different homes wouldn't be such a stretch.
My first thought was that with all I've heard about unscrupulous breeders, this is someone trying to get rid of a couple of unwanted pups. But I guess if it was REALLY an unscrupulous breeder, they'd be asking an arm and a leg for each one and denying there are any genetic problems, if there are.
Sorry, my cynic pops through sometimes before I realize what I'm saying.