That's a very weird thought, Potter as a grandfather. It's somehow much weirder that Albus is his grandson than it is that Albus is her grandson.

Lily nods, though. "I guess that's the most precise way to refer to him, is it?"

Especially not when Milliways is involved. There could be a dozen generations of Potters visiting that place.

... though Lily rather hopes there aren't. Harry and Albus are one thing. She's not sure she can handle being someone's great-great-great-great-great-great-grandmother any time soon.