Reps for the show confirmed his passing to Fox News on Monday.
"We are devastated to hear of Billy Brown’s sudden passing. He has been part of the Discovery family for years - a trailblazer, a lovely man and most definitely one of a kind," the statement read. "Our heart is with his family and those that knew him and loved him as they deal with this devastating loss."
According to People Magazine, Billy's son Bear also addressed the death on his private Instagram, confirming that he died on Sunday after suffering a seizure.
"We are heartbroken to announce that our beloved patriarch Billy Brown passed away last night after suffering from a seizure," read the caption, per the outlet. "He was our best friend — a wonderful and loving dad, granddad and husband and he will be dearly missed."
Bear, 33, added: "He lived his life on his terms, off the grid and off the land and taught us to live like that as well. We plan to honor his legacy going forward, and to continue with his dream. We ask for privacy and prayers during this painful time. God Bless Everyone!"
In 2017, the Brown family relocated to Washington after Ami, 57, was diagnosed with lung cancer so that she could receive treatment.
According to the outlet, they moved to a 435-acre property in the North Cascade Mountains. In 2018, she was told that she was cancer-free.
The diagnosis came after a handful of strange symptoms, as Ami told People at the time.
"I had some pain in my back," she said. "Walking from the house to the garden, I would get winded. There were days I was just bedridden, but I just thought it was my arthritis. We were filming the show and at times it was all I could do to just stand there — I was in so much pain."
She continued: "When we were shooting promo shots I told them, 'There's something wrong.' In December  I went to the dentist to get impressions made for new teeth and when they did a scan they noticed a little capsule. That's how this all started."
The 12th season of "Alaskan Bush People" aired its final episode last October on Discovery.