Do not know if they play Cryptokitties (a virtual pet game on the Blockchain Ethereum platform, traded with Ethereum) together, but what we know is that Sergey Brin said "it's really hard to believe" as mentioned. Zcash's zero knowledge proofs algorithm, in some way combined with Ethereum.
According to Eva Kaili, a member of the EU Parliament, Brin also talked about the data validation and potential of Blockchain technology, that he saw the future of this kind of technology.
I think that this is connected with the hype around this market. All advanced companies want to be "in a trend" and the first to start using blockchain technology in their production. But I think that people who understand this already know for a long time that this technology is behind the future