I just can't stop thinking about James and Sirius in the afterlife, watching over Harry. And when he has his first child, James and Sirius are ecstatic that Harry chose to name him after them. And Remus smiles benevolently and doesn't say anything of course, but maybe feels just a tad left out. Sirius can tell and he pats him on the shoulder saying "Next time! You'll see!"
And then next time arrives and what does Harry choose? Albus Severus. And Remus understands, and he's not really upset. But Sirius is. Sirius just cannot believe that Harry would choose to name his son after Snivellus, the man who had made his godson's and his own life miserable( so what if he loved Lily) honored Remus. Remus, who had been a mentor and friend to Harry. Remus, who had named Harry godfather of his own child. Remus, who was one of the best men Sirius had ever known, despite having a childhood that was much shittier than Snape's. Remus, who deserved to be honored by Harry every fit as much as Sirius did, and certainly a thousand more times than Snape.
And for the first time in his life, Sirius is truly disappointed in his godson. And he can't even let Harry know. He just has to live with this awful feeling for years, and nothing Remus says can make it better.
Until one day Sirius notices something. He notices how there are always four kids at the Potter House. He thought it was just Harry being nice, because Andromeda was getting pretty old by now, but once he starts paying attention, he notices how every time Harry talks about "his kids", that includes Teddy Lupin. How James, Albus, and Lily refer to Teddy as their older brother.
And one day Sirius is watching Teddy risks himself to save Albus from falling of his broom, and then proceeds to fuss over Albus without once worrying about himself. And Harry runs over in panic, and goes immediately to Teddy, checks that he's basically alright, looks at him with tears in his eyes, and says "Teddy Remus Lupin, thank you. Thank you for saving Al. You are so much like your father" And then hugs him tightly and doesn't let go for the longest time.
And Sirius' anger evaporates just like that, and he looks over and sees that Remus has been watching too and now they are both silently crying as they watch Harry, their Harry, take care of two of his sons.
And suddenly it so obvious why Harry didn't name his youngest son after Remus. It was already the name of his oldest.
