A headteacher at a school in Tredegar has said three-year-old Jayden-Lee Lucas and four-year-old Gracie-Ann Wheaton, who died after a crash on the M4 near Newport, "will continue to be celebrated and remembered by us all."
The siblings, from Tredegar, had been returning from a birthday party at around 1.45pm on Saturday February 5 when the car they were travelling in collided with a van.
Jayden and his older sister Gracie-Ann, were rushed to the intensive care unit (ICU) of University Hospital of Wales, also known as the Heath Hospital, in Cardiff.
The children's parents, a man and a woman, were also taken to hospital.
Gracie-Ann suffered a cardiac arrest due to the severity of her injuries and died the following day at around 5am.
Jayden died the following Friday at 4.30pm, his family confirmed
Mr Huw Waythe from Deighton Primary School issued a statement on behalf of the primary school paying tribute to two "special children" who would "put a smile on all our faces daily."
Mr Waythe said: “Everyone at the school is immensely sad to hear of the passing of a second pupil following a road traffic collision on 5 th February 2022.
Our thoughts remain with members of the family, and words cannot adequately express the shock and pain which they must be feeling.
We are shocked and saddened by the loss of two of our own. We will never forget how special the children were to our school community. They both put a smile on all our faces daily. They were a delight to have and both always lit up any room with their positive personality and beaming smiles."
He continued: "Gracie-Ann and Jayden-Lee’s lives will continue to be celebrated and remembered by us all. They both have a special place in our hearts and Deighton Primary School will never forget them.
We will support each other through this, seeking and providing further specific professional assistance for those pupils and staff who find this time the most upsetting.
"We ask that you give us your support by allowing us some time to process our thoughts and feelings.”
Speaking earlier in the week cousin Jamie Lucas, 19, from Abergavenny, said "Unfortunately, after a week of fighting, Jayden has passed away.
"He was wonderful, creative and a kind soul. Turned the grey skies blue."
In a previous tribute to Gracie-Ann, he said: "I'm just trying to wrap my head around the fact that she's gone; it's hard to believe.
"She was so young. She had a bright future ahead of her. She was such a wonderful child.
"I'm just lost for words really. How she was returning from a birthday party and all of a sudden she's gone."
He added: "She was very smart, she was very creative. She had a really great imagination as well. She was just fantastic to be around."
The crash happened on the westbound carriageway between junctions 28 and 29, prompting a huge emergency services response and causing the route to be closed for around seven hours.
The Ford Transit driver, 41-year-old Martin Newman, of Croeserw, appeared at Newport Magistrates' Court on Monday charged with causing death by dangerous driving and two offences of causing serious injury by dangerous driving in relation to the accident.
He has been remanded into custody pending a hearing at Newport Crown Court on February 21.