The joy among Eric Braat and his large group of friends was palpable Thursday night as they stormed the dance floor during their Mount Sinai High School prom at Land's End in Sayville. Each of them knew Braat's hard-won battle had afforded them the opportunity to spend one together, and no one was going to let a moment pass unappreciated.

Braat loves to dance. In 2010, he was selected to perform as a member Knicks City Kids dance team and soon after joined the On the Edge Performance Center competition team in Port Jefferson. What looked to be a promising dance future was abruptly halted in 2014, when Braat spent nearly three months of his senior year hospitalized with Lemierre's syndrome, a rare but life-threatening illness.

Braat became sick in September and was admitted to St. Charles Hospital in Port Jefferson with difficulty breathing and a fever of 104 degrees. After days of tests and inconclusive results, Braat was moved from pediatrics to the intensive care unit and put on a ventilator due to a rapid decline that prohibited him from breathing on his own.

An infectious disease specialist diagnosed Braat with Lemierre's syndrome, a bacterial infection with a mortality rate of up to 17 percent. Due to complications from the illness, both of Braat's lungs collapsed and he required four surgeries, daily blood work and CT scans, along with a host of other treatments.

"I had almost no chance of living, but I needed to push through. I wanted to finish my senior year," Braat said.

Hannah Sullivan, 18, described Braat's hospital stay as terrifying.

advertisement | advertise on newsday

"He's always the one lifting everyone's spirit," Sullivan said at the Mount Sinai prom. "Seeing him not even able to talk was probably one of the scariest things I've ever witnessed."

Braat recalled having at least 15 visitors per day while he was in the hospital.

"Everything felt so final about it -- it was scary. I'm looking at them looking at me as this sick person and just seeing their faces and seeing them crying," Braat said. "It felt like a goodbye."

But after his last surgery, Braat improved and eagerly got back to his life. He would literally sit in on his dance classes to learn choreography while confined to a chair, and met with a tutor to catch up on schoolwork during his recovery.

Though Braat's left lung still has not fully reinflated and he can still feel the effects of his illness, Braat is scheduled to graduate on time and is looking forward to attending City College of New York in the fall.

"It was hard not to dance when I was sick, but I'm finally back to dancing every day," he said. "Honestly, if it were not for St. Charles, I wouldn't have made it."