I think that this is very Harry. It's something that I see Harry very much needing to do for his Godson simply because Teddy is his godson and he wants the very best for Teddy; if Remus and Tonks can't be there for Teddy, then merlin be damned if anyone else would tell Teddy. Never mind the fact that Teddy doesn't understand, it had to be Harry. And I love how you understood this and captured it perfectly.