On Sunday March 3 22-year-old Asad Hussain, a law student, was killed in a car crash in Dewsbury.
West Yorkshire Police were called to Forge Lane in Dewsbury at 12.53pm to reports of a Silver Honda Civic which had come off the road.
The young man was declared dead at the scene.
A 23-year-old woman has been arrested on suspicion of causing death by dangerous driving. She is currently in police custody.
20-year-old female passenger was taken to Leeds General Infirmary with minor injuries.
Garry Oakes, 37, who lives in Mirfield, was travelling a few cars behind. He said: "I didn't see the crash, I just saw the lamppost bent over."
Mr Oakes learned first aid through serving in the Army for six and a half years and working as a site manager.
He said: "I shouted down to the others not to move him because that's the first thing you don't do."
Mr Oakes then approached the drivers side door. He continued: "It took me about five attempts to open it, I don't know how I managed it but I did."
After assessing the situation Mr Oakes decided to take Mr Hussain out of the car to give him CPR.
"I gave him CPR for what must have been 15, 20 minutes but it felt a lot longer.
"I brought him back once but then I lost him again.
"I only stopped when the ambulance arrived and took over."
On Monday, Mr Oakes met with Mr Hussain's family and attended mosque in Ravensthorpe with them as he wanted to give them closure.
He continued: "I didn't know the guy but he was a young lad. I held his hand when he took his last breath. I was there."
Mr Oakes now works as a lorry driver but took the day off having not been able to sleep on Sunday night after the incident.
He added: "I spoke to a paramedic and a policeman because I felt like I'd failed but they both told me I hadn't."
Mr Hussain's family have paid tribute to him. Speaking on Monday, Mussarat Pervaiz, a close member of his family said: "I knew Asad personally and he was a kind, sincere, compassionate young man with a bright future ahead of him.
"He was studying Law at Birmingham University and was very active in charity work.
"He was always thinking of those less fortunate than him and how he could help them.
"I remember him telling me he wanted to raise money to help build wells in 3rd world countries.
"It is such a tragic loss for all those who knew him, especially his family who are all left devastated by this sudden loss.
"Asad will be missed dearly by not only his family and friends but all the community."
Police are appealing for witnesses to contact 101, quoting log number 840 of 3/3/2019.