Nouri's coach at the Amsterdam Arena last season Peter Bosz and former Netherlands internationals Ruud van Nistelrooy and Daley Blind were among those to offer sympathy.
Elder brother Abderrahim said that doctors have informed the family that prospects of Nouri regaining any level of independent living are extremely slim.
"The doctors are quite confident that he will not recover. If he were to wake up, he would not be able to think, eat, talk, walk or even recognise people," he told AD. "He would not be able to function normally.
"But we are not giving up. God will decide his fate. Our religion [Islam] teaches us to accept things and we are praying for his recovery.
"We think this life is only temporary and the eternal comes after this one, but everybody would have liked to see him score goals first."
Nouri made his Eredivisie breakthrough with Ajax last season, making nine appearances for the first team under Bosz.
But it was with Jong Ajax where he truly shone in Netherlands' second-tier Eerste Divisie, scoring 10 goals and supplying 11 assists in 26 matches for Marcel Keizer's side.
Keizer has now succeeded Bosz as first-team coach following the latter's departure to Borussia Dortmund and he oversaw Nouri as he was named Eerste Divisie player of the year for 2016-17.
"This is the worst possible news we could get. It is devastating," said Ajax chief executive Edwin van der Sar. "There are no words to describe what [Nouri's family] are going through."