Harry Dunn's devastated dad has spoken of his heartbreak at not being able to get close enough to hold his son's hand as he lay dying.
The teenager was killed in August after he was struck by a car driven by Anne Sacoolas.
The 42-year-old is the wife of a US diplomat and has since returned to America to claim diplomatic immunity.
Her vehicle is said to have hit Harry head-on after she had driven on the wrong side of the road close to RAF Croughton, an American spy base in Northamptonshire.
His suffering mum Charlotte Charles, 44, and father Tim, 50, are expected to land in America on Sunday to put pressure on Donald Trump to force the mum-of-three to return to the UK and answer questions.
Now they have spoken of the horrific moment they witnessed their son dying.
Grieving Timtold the Daily Mail : "‘I couldn’t get close enough to hold his hand. There were too many people working on him."
His wife Charlotte also spoke of their sadness at not being able to donate his organs.
"There wasn’t anything that wasn’t broken either inside or out," she said, reliving the moment doctors explained the 19-year-old's body was too badly damaged.
"We were only left with tissue donation. I believe that’s the retinas of his eyes and the skin that wasn’t touched."
Charlotte says she has had no communication from Sacoolas, while Harry's father spoke of how difficult the ordeal has been.
Tim described the despair as so awful that it felt like his brain wanted to "explode".
Earlier this week Trump waded into the international diplomatic immunity row and was condemned for his clumsy analysis of Harry’s death.
But in a follow up press conference the US leader softened his stance, revealing Sacoolas was “being spoken to” and that “we’re trying to work something out.”
Lawyer Radd Seiger, who is representing the family, is understood to have arrived in Washington DC on Thursday night for talks.
He said: “Bringing her back to Britain is our priority.”
Prime Minister Boris Johnson suggested that it was unlikely.
He said: “America is reluctant to allow its nationals to be tried overseas. We’ve got to keep working to get justice for Harry.”
