I don't think you mean that but it was the only thing that crossed my mind:
"I did not know you, our lives never touched
Till the day they gathered to bid you farewell
And they painted your picture, and as I looked around,
I felt I saw you in their words and their sound...
"...Your life gave them a treasure, a piece of themselves,
Something to carry, and it still serves them well...
"...And what you've left behind you, and what swept over me,
Says that your life's world grows on and on,
a piece of eternity..."
"Just One Life" by Brian Harold May
That is not about Freddie Mercury (Just one Life). Can't recall the name of the person right now, but Brian mentioned this once.
My thoughts of a poem about Freddie would be No-one but you, although this song can reflect to many people (again as Brian said, such as Princess Diana).