Why did the cast of Alaskan Bush People leave Alaska?

THE ALASKAN Bush People family relocated to California to be treated at UCLA Medical Center after Ami was diagnosed with advanced lung cancer.
Here's more on the hit reality TV family and their recent upheaval.
What is Alaskan Bush People?
are a family from Alaska’s wilderness.
For more than eight seasons, the hit Discovery Channel’s reality TV show has followed the Brown’s daily life in the wilderness as well as that of their seven children.
Ami Brown, 55, and her husband Billy, 66 live with their five sons, Matt, 36, Bam, 34, Bear, 31, Gabe, 29, and Noah, 26, and daughters Bird, 24, and Rain, 16, in Washington State.
Billy is thought to be worth over $6 million, and reportedly earns around $500,000 for the show.
His kids are thought to be paid about $40,000 to $60,000 each.
Recently, the Brown’s eldest son, Matt, stopped filming for the show and to battle substance abuse.
Earlier this year, to a boy and are now facing custody battles in regards to their son, River.
The couple did not specifically cite their reasons for separating, however, Raiven has vowed to keep the couple's newborn son away from Bear.