Kenny Pemberton had dreamed of his club reaching the famous old stadium, but sadly died of a heart attack last year aged 49.
Wrexham face Welsh rivals Newport County in the one-off match to decide who reaches the Football League.
His brother Paul will take the urn to North London.
“Kenny always dreamed of watching Wrexham at Wembley," he said. "If he were still with us he’d be the first there. So this is my tribute to my brother for all he did for the club.”
Kenny was a hero at the club, having made secret recordings of a conversation with a former chairman who wanted to sell off their Racecourse Ground home.
He fought in the High Court to make these public and help new owners take over and safeguard the future of the ground.