“It was his decision to drop everything and go fix what he hadn’t fixed,” dad Billy Brown says of Matt Brown

Alaskan Bush People star Matt Brown has completed his second stint in rehab for alcohol abuse.

The eldest son of the Brown family — who rose to stardom on their hit Discovery reality series — completed six months of combined inpatient and outpatient treatment in January, PEOPLE exclusively confirms in the current issue of the magazine.

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“It was his decision to drop everything and go fix what he hadn’t fixed,” dad Billy says of Matt, 36, who first went to rehab in 2016. “He’s fighting a hard road. He has for a long time. We just try to let him know that family’s here no matter what.”

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“I could see myself spiraling,” Matt told PEOPLE after completing treatment the first time, explaining that once he began spending more and more time drinking with friends “in town” over the previous year, “I was more withdrawn. I was slower. Things didn’t excite me the way they used to.”

For more from the Alaskan Bush People — including an exclusive statement from Ami’s doctors about her cancer battle — pick up the current issue of PEOPLE, on newsstands Friday.

Matt said he first started drinking a few years ago when his family‘s boat broke down off the coast of Alaska and they began spending time in nearby Juneau.

“I’ve always been able to handle city life, no problem,” said Matt. “But I started hanging out with people who drank. They didn’t have a problem with it so while I was around them, I started drinking.”

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While the rest of his family rebuilds their lives in rural Washington State after mom Ami’s battle with advanced lung cancer, Matt continues to live in California, where he attends support sessions and is working to maintain a sober lifestyle.