'Alaskan Bush People' Star Matt Brown Dead at 43

Matt Brown -- the reality star who appeared on almost 80 episodes of "Alaskan Bush People" -- has died, according to his brother.

Bear Brown just posted a TikTok with the sad news ... and he's clearly still very shaken up, saying he never imagined his brother would hurt himself, confirming Matt took his own life.

Bear asked people to be respectful and kind ... and not leave nasty comments since the family is still reeling from the tragedy.

TMZ obtained dispatch audio from the initial search for Brown's body -- you can hear responding personnel note his backpack was uncovered while his gun was thought to be in the water ... and that his body was not with it. They also ordered a search boat and dive team.

Brown caused concern on the internet back in May when he live-streamed himself on YouTube ... during which he rambled incoherently and wandered around a town in Washington state.

He appeared nude and possibly intoxicated ... and even held what appeared to be a gun at one point as well.

Family sources told us most of the fam cut Matt off about five years ago because they could not longer support him amid his ongoing addiction struggles.

Gabe Brown is the only family member who communicates with Matt, we're told ... and our sources made it clear their chats are few and far between.

Despite the estrangement, Matt's family expressed concern about his disappearance ... with his brother Bear sharing a video in which he mentioned people saw Matt near a river and he was floating in the water at one point.

"Alaskan Bush People" follows a family as they rough it in the state's wilderness ... living off the land in a small community known as "Browntown." Critics have questioned the show's authenticity.

Brown appeared in 79 episodes of 'ABP' from 2014 to 2019. He was 43 years old.