how do you know if your grandfather is happy?

That's very easy.
Gaizka's grandpa Antonio Paiva Reinoso has a peculiar way of expressing his joy and his pride.
When I started my architecture studies at the university in 1985, my father told me that he had told his university students early in the morning that he was very happy and proud that his first son had started at the university the very same day.
When I got my PhD in Utrecht in 2003, my father told me that he had told his post-graduate students that his son was getting a PhD diploma in Holland!
And when Gaizka was born last september, my father told me that he had told his post-graduate students that the day before his dutch grandchild was born.
So, Gaizka, grandpa is very, very happy. You can tell.