"It just snuck up," Westwood Police Sgt. Scott McNiff Daily Voice.
Rahl, 57, who next month will have worked behind Davey's bar for 30 years, has a wife and a daughter.
"Mark has been so close to all of us over the years. We have gone to weddings and family events together," McNiff said. "I remember him coming to my father's wake.
"Mark is much more than just our favorite bartender at our favorite pub," he added. "The Police Pipes and Drums of Bergen County love him. The law enforcement and first responders throughout the area -- and even into NY -- love him.
"He is a friend, an ear who listens to us when we go through tough times, and someone who could make you laugh until your sides ached with his sense of humor. We pray for him and his family during this difficult time," McNiff said.
Friend Terry Kane Maffei established a GoFundMe page for Rahl.
"We are asking, on his behalf, to help offset the seemingly insurmountable medical costs he and his family are facing," she wrote. "A son, a brother & friend. He has been our bartender, a comedian & confidant putting smiles on our and our customers' faces for over 30 years."
Click here to follow Daily Voice Pascack Valley and receive free news updates.