Eight years. Remus knew, of course, but hearing a number somehow made it even more real than seeing Teddy first in his twenties and now at sixteen. Life passed by without him. He didn't really allow himself to think about anyone missing him. He spent most of his adult life missing people, but now that Harry said it, he realized he hadn't really thought he left much besides Teddy behind. Everyone had a family or friends who were good as family. Most of the people he knew died before or with him. Even Teddy was too young to actually miss Remus for Remus. He missed the idea of his dad.
Maybe he underestimated his importance to those he loved in his time. "I don't want to say I am glad, but...it is nice to know," he admitted. "Talk to your parents, Harry. Really. I think you'll be glad you did."