Stuart Richards, 32, was driving home from Gatwick airport when he was hit in the fatal M40 crash on Monday.
Today his distraught younger brother Niall described him as the family's "rock".
But he added that he was left reeling when he discovered the driver that killed Stuart had been in a crash just five days earlier.
Niall told the Mail Online: "It could have been completely avoided if certain things had been put into practice.
"This is the world we live in – under police cuts and roads not being looked after properly.
"Right now, we are more angry than upset."
Niall and his dad found out the other driver had crashed the same Subaru car involved in the fatal smash when they identified Stuart's body.
Tragic Stuart had just finalised the sale on a house in Stockport with his girlfriend of five years Ashley Crawford, from Belfast, on the day he died.
Niall had been waiting at Stockport station to meet his ex-squaddie brother when Ashley arrived in a police car.
He added: "She is absolutely devastated, obviously.
"We are a very tight family and we are all devastated – he was my best mate."
Movie fan Stuart had just arrived from a trip to LA and was driving to pick up his brother when his Ford Mondeo was hit head-on on the M40.
And the Coventry city fan was just back living in the UK after three years abroad in Australia — where he moved after becoming disillusioned with the army.
Harrowing dashcam footage showed the speeding Subaru narrowly missing other motors before smashing into Stuart's car.
The tragedy had been referred to the Independent Office for Police Conduct after it was revealed the Subaru had been involved in another damage-only crash five days earlier.
A police spokesperson said: "Thames Valley Police has made a mandatory referral to the IOPC in relation to the fatal collision, due to previous police contact."
Panicked motorists had been forced to swerve out of the way of the Subaru on Monday afternoon as it sped the wrong direction down the northbound lanes in South Oxfordshire.
The car is believed to have been on the motorway for eight miles — swerving across lanes for seven minutes before the crash.
The driver and passenger of the Subaru Forester, both in their 80s, were also killed and are yet to be formally identified.
Tributes have flooded in for Stuart, who had a glittering career as a soldier in the British Army where he served in war zones in Afghanistan, Iraq and Jordan.
Stuart had also worked with spells overseas in Germany, Canada, Norway and across the UK.
He had most recently been working as a Health and Safety officer for The Emerson Group in Stockport, Manchester.
Hayden Jones, the building manager at the apartment block where Stuart previously lived, added: "I used to chat to Stuart quite a lot. He was friendly and easy going, a really nice fella.
“They were a lovely couple and when they moved out they send me a card which said ‘thanks for looking after us’.
“It’s such a shock what’s happened.”
Girlfriend Ashley was too upset to comment earlier this week, appearing tearful as she arrived at the home she shares with her father in Stockport.
Neighbours of the young man's parents also expressed their shock, with Paul Horton, 73, saying: "It’s a terrible way for any family to lose a loved one."
Stuart had also previously worked with Persimmon Homes.
Mark Cook, regional managing director of Persimmon Homes North West, said: “Stuart only worked with us at for a short time, but everyone in the team is shocked and saddened by this tragic news.
"Our thoughts are with his family.”
Witnesses had previously claimed the car had foreign plates after seeing it travel down the motorway — but police later confirmed the Forester was registered in the UK.
West Oxfordshire councillor Colin Dingwall witnessed the crash, saying: "I’ve seen a lot of things in my 50 years on the road, but never a caravan coming the wrong way up the M40.
“Luckily I and the cars near me managed to pull into the middle lane and get out of the way.
“I had about two seconds to react.”
Another witness said she saw the Subaru "heading towards" her.
A Thames Valley Police spokesperson said they had received reports about the car about 4pm on Monday, October 15.
They said: "A few minutes later, the vehicle was subsequently in collision with two other cars, a Ford Mondeo and a Ford Focus near junction 6.
"The driver and a passenger of the Subaru, both aged in their eighties, died. They are yet to be formally identified at this time.
"The driver of the Ford Mondeo also died. He has now been formally identified as Stuart Richards, aged 32, from Stockport, Cheshire.
"Thames Valley Police has made a mandatory referral to the IOPC in relation to the fatal collision, due to previous police contact.
"On 10 October this year in High Wycombe, a report of a damage-only road traffic collision involving the Subaru Forester was made to the Force.
"The IOPC will now make a decision as to whether they will carry out an investigation."
The M40 in South Oxfordshire was closed for for several hours as emergency services dealt with the casualties and traffic officers gathered evidence.
It was the second triple fatal collision on the Thames Valley's roads in 48 hours as three special needs teachers were killed when in collision with a lorry on the M4 motorway.
A spokesman IOPC said: "We are currently assessing a referral from Thames Valley Police to determine the level, if any, of our involvement following a fatal road traffic collision on the M40 in South Oxfordshire on Monday, October 15.”