Donna Sharp, 41, of Firle Road, Eastbourne, said, "It has been the most horrific six weeks of my life."
But added, "I've done my crying and I've done my worrying. If I'm not positive then how can he be positive."
Now that her son is out of danger, Mrs Sharp has decided to do a skydive to raise money for Help for Heroes, a charity which helps injured soldiers.
Mrs Sharp, who has four sons, is a mortician at Eastbourne District General Hospital. She said it was 'the worst day of my life' when, on a Thursday in August she was interrupted at work and taken into a room to find two military representatives waiting for her.
They asked if she was the mother of 21-year-old Rifleman Christopher Howard of 2nd Battalion the Rifles.
Fearing the worst, she said, "He's dead isn't he?"
The representatives explained that her son, who grew up in Molesey, Surrey, was alive but classed as 'VSI', or very seriously injured.
She said, "They told me he had lost a hand and a leg."
She drove straight to Birmingham so she would be at Selly Oak Hospital, where military personnel are treated, when the plane carrying her injured son landed the following day.
Her ex-husband, Rfm Howard's father, flew from his home in Australia to be at his son's bedside.
It was August 13, a few days before the Afghan elections, when Rfm Howard was on foot patrol in Sangin when an IED – or improvised explosive device - exploded.
The bottom half of his right leg from the knee down was blown off as was the little finger, ring finger and middle finger of his right hand.
As a helicopter was landing to attend to those wounded in the blast, a second device exploded killing three of his comrades: Captain Mark Hale, 42, and Rifleman Daniel Wild, 19, both of the 2nd Battalion the Rifles and Lance Bombardier Matthew Hatton, 23, from the 40th Regiment Royal Artillery.
A week later, Rfm Howard's sergeant, 29-year-old Sergeant Paul McAleese, was killed in a separate incident.
Being aware of the four deaths and meeting other injured soldiers and their families in hospital, Mrs Sharp said she feels fortunate. "He's okay. In a way Chris is lucky."
Rfm Howard was 19 when he joined the army and has been on several tours of duty, including in Kosovo.
He had been in Afghanistan for six months and was just six weeks away from finishing the tour when the blast happened.
Mrs Sharp said, "I was dying for him to come home. He had been out there for six months and I'd had enough of worrying."
But despite the worry and the trauma of the past six weeks, she is supporting her younger son who has decided to join the army.
Nineteen-year-old son Lee Howard made the decision to join-up three weeks after his older brother was blown up.
On Monday (September 28) he collected the paperwork to apply. His mum is backing him. "I told him to go for it," she said.
Rfm Howard was critically ill and underwent several operations. Mrs Sharp has been at his bedside throughout and was there when, on September 2, he was visited by Gordon Brown, who was touring the hospital.
Asked what the prime minister said to the wounded soldiers, Mrs Sharp said, "He told them what good lads they are."
A few days later when she returned to Eastbourne, Prince Harry visited the hospital.
Rfm Howard was determined his mum would not miss out so Mrs Sharp got a phone call from the third in line to the throne.
She said she was surprised but not nervous. "It was totally normal. We were just chatting. He is a really, really nice bloke," she said.
Rfm Howard is now in a wheelchair in Selly Oak Hospital from where he will move to the Headley Court rehabilitation centre in Surrey where he will get a prosthetic leg and go through physiotherapy.
Mrs Sharp does not know how long he will be there but expects it to be at least a year. She said her son plans to continue with his military career.
"He's staying in the army. It's what he joined."
Mrs Sharp is full of praise for the army and the hospital, and wants to thank them and her friends and family for their support.
She has not booked a date but this week decided she wants to jump out of a plane to raise money for Help for Heroes.
She said the charity has been wonderful to her and other people she has met. The charity provides practical support including accommodation for relatives of wounded soldiers.
Mrs Sharp said her decision to do a skydive and her determination to cope with her son's life-changing injuries comes from within.
She said, "You have to think positive. I'm a very positive person and so is Chris."
She added, "There's something special about Chris. I always said he was brought to me by the angels.
"He'll get over this. He'll accept and he'll move on."