Christie Brinkley shared that her ex-husband Billy Joel is on the mend almost a year after being diagnosed with the rare brain disorder normal pressure hydrocephalus (NPH).

The model told Hello! Magazine on Tuesday, “He’s doing very well.”

The disorder occurs when cerebrospinal fluid (CSF) builds up inside the skull and presses on the brain, disrupting cognitive functioning.

Along with the support from Brinkley, 72 — who was married to the musician from 1985 until 1994 — and their daughter, Alexa, 40, Joel, 76, also has his wife Alexis Roderick, 43, and their daughters, Della Rose, 10, and Remy, 8, by his side.

Last month, Alexa honored her dad during Carnegie Hall’s “The Music of Billy Joel” tribute event.

She sang “This Night” at the concert — which couldn’t have been sweeter, according to Brinkley.

“She was so excited to be able to perform for him,” the cover star gushed to Hello!. “I was sorry that I had to miss that night.”

“I was out of town,” Brinkley added, “but otherwise it was so wonderful.”

Just hours before Joel was honored, Alexa gave her own updated on the “Uptown Girl” singer.

“He’s doing physical therapy regularly and he’s doing great,” she told the Hollywood Reporter at the time. “He’s lost weight as he’s on his diet.”

Alexa continued, “I’m so proud of him. He’s such a trooper, so resilient and committed to being healthy and proactive. He’s a fighter. He’s always been a fighter and talks in his documentary about how life’s like a fight.”

Joel first revealed his shocking NPH diagnosis in May 2025, forcing him to to cancel a series of tour performances.

His condition became worse due to his concert performances at the time, “leading to problems with hearing, vision, and balance,” his lengthy Instagram announcement read.

The doctor ordered the Grammy winner to “refrain from performing during this recovery period.”

He then released a statement in July 2025 reassuring fans he was doing fine and staying positive.

“It was scary, but I’m okay,” Joel admitted to People at the time. “I just wanted to let people know, don’t worry about me being deathly ill or anything.”

“I’m doing my best to work with it and to recover from it,” he added.

More recently, the “Movin’ Out” crooner surprised fans with his first performance since revealing his NPH brain disorder battle.

Back in January, Joel took the stage — with the help of a cane — during a celebration for the 30th anniversary of Wellington, Florida.

He was joined by his wife and their two daughters, and played his hits “We Didn’t Start the Fire” and “Big Shot.”

Joel teased: “I wasn’t planning on working tonight!”