They don't name their daughter after him, but Shirley is close enough and that actually makes him smile.
He catches himself as he's about to run a finger over the infant's features. She looks like John, but for her eyes; those are Mary's eyes, and therefore vaguely reminiscent of Sherlock's.
His heart swells with pride at the thought that he's the uncle of John's child. They're family, no matter how strange it may seem.
Mary smirks, steals a glance at John as he's making tea.
"I wouldn't mind sharing," she says wryly, but Sherlock just pretends he can't hear her.