BROWNSVILLE, Brooklyn (PIX11) — People gathered somberly in Brooklyn on Sunday to honor an FDNY hero who suffered a fatal fall.

William Moon, a 21-year veteran of the FDNY tragically fell at least 20 feet Monday while preparing for a fire drill at his Brownsville firehouse on Sterling Place. After it became clear Moon would not survive, his family decided to donate his organs.

Black and purple bunting now hangs from Rescue Company 2. Firefighters surrounded nearby streets to memorialize Moon, 47, on Sunday.

“We’ve lost the perfect human,” Rescue 2 Commanding Officer Captain Liam Flaherty said.

Moon’s comrades honored one of their own, alongside the firefighter’s beloved family.

“If you were having the worst day of your life, you’d want Billy Moon riding in that fire truck there. If I was trapped in a burning collapse, I’d want Billy coming for me,” Cpt. Flaherty said.

Described as a “firefighters firefighter,” Moon also served as a member of the Islip Volunteer Fire Department. The Long Island native leaves behind his wife and two young children.

His organs will be donated to save the lives of others.

“It’s so selfless to give everything to save others, it’s a perfect firefighter model of credo,” Cpt. Flaherty said. “Billy was a selfless warrior who gave the gift of life and the life thereafter. The ultimate Santa Clause bringing life to people at Christmas.”

Moon’s loved ones and the men and women who courageously work to keep New Yorkers out of harms way are now preparing for their final goodbyes.