The brave teenager passed away last Monday, but mum Alison Barr insisted his memory would live on through a charity set up in his name.
And the 44-year-old said flowers arrived addressed to herself, his girlfriend and his grandmother – with a poignant handwritten note telling them he loved them.
She said: “It’s been very much a rollercoaster – up and down. We’ve had times where I’ve just burst into tears, and other times where I’ve managed to be really strong and smile.
“When I got the flowers from my beautiful son the other day I just fell apart. He had arranged flowers to be delivered to me, my mum and his girlfriend – and he had given Amy, his sister, flowers before he passed away.
“They came the day after he passed away, with a handwritten card by himself. It just said on it, ‘To mum, I love you and I will look after you. All my love, Jak’. It was just beautiful.”
A charity football game in Jak’s honour yesterday saw 4000 people pack into Livingston FC’s Almondvale Stadium – raising more than £13,200.
The fast-paced clash saw the teenager’s old under-16s team Mid Calder Colts play against teachers at West Calder High, where Jak had been a pupil.
And both sides were helped by a raft of football stars, including Celtic legend Frank McAvennie, Hearts goalie Neil Alexander and former Rangers players Nacho Novo, Charlie Miller and Marvin Andrews.
Fighting back tears during an emotional speech before kick-off, mum Alison dedicated the day to her “beautiful, brave and inspirational boy”.
She added: “I’d give anything to have saved him and to be one of the proud mums standing here watching their boys play, but I know that sadly that wasn’t to be.”
The match – dubbed the Jak Trueman Challenge Cup – saw the teachers triumph 5-3, but that didn’t stop the stadium echoing with cries of ‘There’s only one Jak Trueman’ as his school mates rallied behind his old team.
Speaking after the game, former Rangers defender Marvin Andrews said he had been “touched” by the experience.
He said: “When I came into the car park this afternoon and saw all the cars, it looked like a First Division game. I couldn’t get parked anywhere. I was really touched by it. I’m really happy to be part of it.”
Evan Ramsay, who helped coach the Mid Calder Colts and had known Jak for three years, said the day had proved a fitting tribute. The 20-year-old said: “It was a fantastic event. It’s great to see so many people here. Even for his mum and sister, it’s something to look back on and remember. Jak was a brilliant lad and a fantastic guy – he’d do anything for anyone.”
Jak was diagnosed with a very rare form of blood cancer – known as Gammadelta T-cell lymphoma – in August. A fundraising page for leukaemia and lymphoma research set up during his final days has since raised more than £50,000 – well over double the original target.
His family now plan to set up a charity in his name – dubbed Team Jak – to fight cancer, with plans for a purpose-built hall entering the early stages.
Mid Calder Colts coach Alan Porter said: “Jak’s going to leave a huge legacy.”