The attacker, a 39-year-old woman, was taken in custody and no motive for the assault was released.
The Islamic State claimed responsibility.
He suffered brain trauma.
Two girls are also in serious condition after Saturday's attack.
Police said they are investigating whether there was an Islamist motive to the attack.
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Alicia Martin And Kathryn Rayannic's Rejected Flash-For-Beer Offer Turns Into Knife Attack, Police Say
That's when things got ugly. The Waterfront employees say they confiscated Martin's car keys. Lee County sheriff's deputies