That's all very nice. But Michael Douglas was married to someone else previously, and if I'm not mistaken, Michael and that wife had children (someone correct me if I'm wrong, please)... so, isn't Kirk also the grandfather of those children? LOL. How soon people forget.
Those were my thoughts as well - also - doesn't he have other children, not just Michael? That's odd he would leave them out.
Of course he knows, silly. He is mentioning the two grandchildren as the children of Michael and Zeta-Jones only...remember he is speaking to GenY-ers and trying to connect with what they know. Remember the context.
Kirk Douglas has 5 sons, one is a special needs child, I believe. Parade magazine did a write up on him a while back. He mentions his famous son and daughter-in-law, because so many may not remember him, but they will know Catherine Zeta-Jones.