My son has met three of his grandparents (out of four, or, counting step-grands, five out of six). My dad, however, passed away before his grandson (my son) was born. I rarely talk to my son about the grandfather he hasn’t met, because I’d like to hold that off until a time and setting that seems best comes along. However, my son does know about “Grandpa Rup,” and has asked me a few questions, which I do always answer. So, he knows that his grandfather was, among other things, in the Navy for many years.
Every year, on Grandpa Rup’s birthday, we fill a helium balloon and write a greeting on it, then let it go together, watching until we can’t see it anymore. Something new came along today, to add to that. His grandson wrote my dad a note. Here it is:

That is so beautiful.