Mohammad Hayyan Hoor, 13, died at Leeds Children's Hospital in May last year.
He was admitted to hospital in May, 2021 following undiagnosed headaches and fevers. He was previously fit and healthy.
His mum, Farah, said: "He was a really good boy, really active and just loved by everybody. He was a really mature child and just had something special about him.
"He was a pupil at Wetherby High and he really loved his school and was such a popular kid."
Hayyan's dad, Haqnawaz, added: "He was my best friend so wise and had so much wisdom, we did almost everything together, I could count on him for anything
"Our world shattered the day he left, but we have to be strong for our other children.
"He absolutely adored his younger brother and was a best friend to his sisters."
Mum, Farah, is now raising awareness and urging parents to be vigilant when it comes to their child's health,
Farah said: "We wanted to tell our story and to encourage other parents not to allow themselves to be pushed back.
"If you feel like something is wrong then speak up.
"A lot of parents will dismiss these things and go: 'It's ok, they will be fine, it's nothing, it's just a viral infection'.
"And it was just a viral infection but it got out of hand and his little immune system couldn't handle it."
After complaining of severe headaches following his admittance to hospital, Hayyan began to have seizures and was moved into the intensive care unit. He died in hospital.
While the family decided not to pursue a coroner's court hearing, an incident investigation was launched by Leeds Children's Hospital.
Dr Phil Wood, Chief Medical Officer and Deputy Chief Executive; “It is deeply upsetting for everyone, including the medical team, when a child dies in their care.
"Hayyan was diagnosed with a very serious rare condition and in spite of the best efforts of the medical team, his condition deteriorated very quickly.
"Our deepest sympathy goes to his family and friends.”