This statement could be taken as implying that Buffet is cheap and that money is all he cares about. That could all be true, but it could also explain why Buffet is so incensed at her.
Now that he's gone to the trouble of publicly disavowing her as his granddaughter, conspicuously pointing out that she's never been adopted and is not legally related to him, she is countering that with her own claims. That strongly suggests (at least, to me) that the two of them are positioning themselves for future litigation concerning his estate. Somehow, I don't think their difficulties with eachother are something new.
That's not exactly what he said- he said that he never legally adopted her as his grandchildren, which is silly since it only matters if his son legally adopted his stepdaughter.
Three of us are quite involved (especially me, since I live in the same town!), but one brother, 150 miles away, has virtually removed himself from the family once the "dollar situation" became known.