Friends pay tribute to man killed in Mt Eden crash

Police want to hear from the driver of a blue BMW who they believe may have witnessed the crash that killed a father and son, and left a toddler seriously injured.

On Friday doctors switched off life support for the one year-old boy who was critically hurt in the road crash on Tuesday.

His father, Christopher Tobin, known as "Tuffa", was also killed when the car he was in with his children hit a bus.

Only a few days earlier the devoted father of three visited his friends at their home in the Waikato.

Chris, Olivia and their children had intended on only a brief visit, but they ended up staying the night.

Friend Kim McGregor says they lost track of time, "singing and joking".

"It was just a really beautiful night and lots of laughter.

"His treasures were his lady - his wife and his beautiful children. That was evident with everything he did... his actions, what he spoke."

"He had the most amazing special heart," family friend Rebecca Keiser added. "You'd meet him and it would feel like you've known him forever."

Ms McGregor's partner has cancer and it was Chris who offered to help do odd jobs around the house.

They've set up a Givealittle page to help Chris' family.

"I actually said to them that they were a blessing, and that's why my heart wanted to return the same blessing."

It was a tragic scene in Auckland's Mt Eden immediately after the accident. The crumpled remains of the car Chris had been driving could be seen draped in green plastic.

The couple's one year old Jack, who was in the backseat with his sister had just started to walk.

Now his friends are planning multiple funerals - but say they'll never forget the genuine Kiwi joker whose life was his family.