It’s been years since Greg’s sung anything in front of an audience. Anything real.
The Yarders know he can sing. He used to be in a band, and anyone in a car with him learns quickly that he controls the radio, singing and drumming along on the steering wheel. Sometimes he’ll even sing softly to himself around the office if he’s got a song stuck in his head.
What they don’t know about is all the times he stayed up all night in Sherlock’s flat, nervously pacing and drinking cup after cup of coffee while he waited for Sherlock to come down from a high. The flat was horribly quiet so Greg would fill the hours by singing to himself, whatever came to mind.
That’s how he found out that Sherlock’s mother sang to them when they were boys. He doubts Sherlock even remembers telling him, shining with sweat and glassy-eyed as he’d been at the time.
But Sherlock had also said that he liked Greg’s voice, and he would wave his arm clumsily, conducting Greg before he slipped back into unconsciousness. It was probably just ego and imagination but Greg thought Sherlock slept better when he sang, so it became a conscious habit that died out along with Sherlock’s drug use.
At Sherlock’s funeral he feels like he’s run out of words to say, so he sings someone else’s words instead.