"I got into the ambulance with him and he was blue-lite straight to hospital.
"Stuart drove in his car behind, he was seen straight away at the hospital and the doctor said that he'd need to see a specialist.
"I went with him to Addenbrookes where he has a CT scan and went straight into theatre.
"It was a life or death situation and I was terrified, I haven't left his side throughout- I have to thank The Sick Children's Trust for providing me with accommodation throughout the time Grady was in hospital."
Grady was put into an induced coma, and was on a ventilator to breathe for him while he was recovering in hospital.
Grady fractured his eye sockets, cheekbones and his nose and split the roof of his mouth and both his upper and lower jaws.
Julie said: "He had to have six metal plates screwed into various parts of his jaw and a probe inserted into his skull to check the pressure inside his head.
"He's been on morphine, muscle relaxants, everything - he's just come out today and he's made a fantastically quick turn around because he really is so, so fit.
"Grady spends every spare second of his on his bicycle and is desperate to get back on, but the doctors say that he needs to wait until at least the next year, and will have to wear a full face helmet if and when he does.
"He'd just has his braces taken out the day before the accident, and we've now learnt that if he'd still had them in, he'd probably have lost more teeth."
After five hours of surgery to restore Grady's facial structure, doctors are still unsure about the future for Grady but are amazed at his speedy recovery.
"When Grady's over 18, he'll be able to get porcelain teeth- we're just taking it step by step for now and everyday he's getting so much better.
"Obviously one of the main things that Grady is worried about is the permanent damage that will be done to his face, but he's getting better every day.
"Doctors have also alerted us to other possible future problems, like chronic fatigue and loss of concentration, which we have to warn the school to look out for.
"He'll he to be slowly introduced back into school in a few weeks, firstly just for shorter days and then for full days but with longer breaks.
"I'm so grateful that he was wearing his helmet, the doctors have said that his head injury would have been far worse if he was not wearing one."
Julie said it feels that the council should put up advisory signs about the importance of wearing a helmet when using the ramps.
She looks forward to thanking the boys who used Grady's finger to unlock his phone and called her when he was injured.
Julie said: "I would like to thank the two boys who thought really quickly to get my son's phone and get his fingerprint to call me and then call an ambulance.
"Their quick thinking has probably saved my son's life."
A spokesman for Huntingdonshire District Council said: "The council takes safety very seriously and we have signs to promote safety at the skate park in Hill Rise and all parks managed by the district council.
"We are very concerned to hear of this accident and wish Grady a full and speedy recovery."
The spokesman added: "We are happy to work with his parents to raise awareness of wearing helmets which do save lives."
Grady, who is 6"2, was doing an air trick at Hillrise ramps in Cambridgeshire, and was rushed to Hinchingbrooke Hospital.
He was then transferred to Addenbrooke's Hospital, in Cambridge.
Brother Harvey, 16, is relieved to have his brother, who is a pupil at St Ivo School, back in his family home in St Ives, Cambridgeshire.