Mrs Lints was also injured in the crash, breaking her left wrist and fracturing her pelvis.
Haydn Lewis Boyle, the driver of the van that ploughed into them, was convicted on two counts of careless driving causing injury and will be sentenced this Friday.
With the anniversary of the crash and sentencing falling within a day of each other, and another baby due in a month, it is a time for closure and new beginnings.
"It seems like it was so long ago because we have been through so much since then [and yet] a year seems to have flown," a heavily pregnant Mrs Lints said.
After the crash, it was thought Aiden would have no movement from the waist down.
But as he rolls around on the floor, play-fighting with 20-month-old Danyon - affectionately referred to as "Danger" - it is clearly not the case.
While he cannot stand on them unassisted, there is power in his little legs as they lash out in defence.
"Every little bit of movement there has been since then is a miracle," Mrs Lints said.
In December, a touch test showed he had feeling right down to his toes. "You can tickle his feet and he can feel it."
And three weeks ago when he had a check-up at Starship Children's Hospital they were told he was progressing so well he would not need to be seen for another year.
Meanwhile, he will continue his daily exercises and weekly physiotherapy and swimming sessions. "We're rapt with how far he's come. He's doing awesome," Mrs Lints said.
Because of his age and the fact his spinal cord was only partially severed, it is unknown how far he will progress, but the Lints have been told he will never walk "normally" again.
"He will always need splints and a wheelchair for life. That has been indicated all along," Mrs Lints said.
However, given his fierce determination and the technological advances that could occur in his lifetime, they are optimistic.
"We know he'll be fine. One day he'll just get up and do it. I've said that all along. I've listened to them - they're the experts - but as a mother you think you know your child best, I suppose, and he's young and he's got time on his side."
Although he is more withdrawn than before the crash, he "just gets on with it", Mrs Lints said.
"He's very determined to do things for himself, which is incredible when you think about it."
Aiden has not asked the hard questions yet but heart-breakingly tried to follow in his little brother's footsteps when he started to walk.
"Aiden tried to stand up and walk and realised he couldn't," Mrs Lints said.
She told him: "Don't worry. One day you will walk. I promise you."
