Damien Wesley Marshall Reeves was yesterday found guilty of causing 25-year-old David Kearnes's death by dangerous driving.

Jurors deliberated for less than 25 minutes before returning the unanimous verdict at the end of Reeves's two-day trial.

The crash occurred on a Highland Lakes Road bend, 2.5 kilometres away from Deloraine at 7.30pm on December 4.

Mr Kearnes was killed instantly when Reeves' black Holden Commodore left the road and slammed into a large tree.

His speed was estimated at 126 kmh on the bend.

Reeves's brother was seriously injured in the crash.

In her pre-sentencing submissions yesterday, Reeves's defence lawyer Tamara Jago, SC, told the court the father- of-two was "completely and utterly devastated" by the death of the friend he considered a brother.

"He has recurring nightmares (about the crash) and says he has become a very different person since the accident," she said.

Ms Jago said Reeves often found himself crying and had become very withdrawn.

"He often goes to Mr Kearnes's grave, where he will just sit and reflect and wish to have that afternoon all over again," she said.

Reeves's heavily pregnant partner broke down in tears as the guilty verdict was read to the court.

Ms Jago said the scaffolding site manager could not comprehend "how it had all gone so horribly wrong".

Chief Justice Ewan Crawford remanded him in custody ahead of his sentencing tomorrow.