OK, that's already a good start. Have the KfW give you in writing that the small real estate share is really a killer. According to the legislator, that can't have been the intention, as it explicitly refers to (usable) residential property and not to any kind of assets.
Yes, that's the bad thing about it. But where do you want to draw the line? My situation is really similar. A few years ago, my parents transferred the parental home to my brother and me with lifelong right of residence. In this case, this real estate possession is currently "worth" nothing to me, but I still don't receive any Baukindergeld. We did not count on the money, so it's not quite as tragic as in this case. But it would have been nice.
As far as I remember, only 1.5 billion euros were provided for Baukindergeld. Then they probably quickly realized that this wouldn't last long. After that, they first shortened the time period and then introduced the trick with real estate ownership. And voilà, a very large share of eligible persons is already excluded.
My colleague bought his house on 16.12.16. 14 days too early to receive Baukindergeld. For him it would also have been 24,000 euros.
None of this is fair, but getting upset doesn't help either.