By 2008, Osmond and her eight children had left Utah and the home she had shared with her ex Brian Blosil, headed for a new life in Las Vegas, her career rejuvenated by her appearance in 2007 on Dancing with the Stars.
It was a fresh start for her son Michael, too.
Back in 2007, the teen spent time in rehab for substance abuse. At the time, Osmond's brother Donny told PEOPLE that his sister had been dealing with Michael's issues "for a very long time."
But by 2008, Michael, a talented musician and high school senior, appeared to be doing better: Mom boasted in her book Might As Well Laugh About It that he "had been accepted into a performing arts program for high school students."
Last fall, he enrolled in the Fashion Institute of Design & Merchandising in Los Angeles. One of Michael's close friends says he "was happy" and "loved" L.A. – and the move made Osmond happy, too.
"Wow, I'm proud of that kid!" she Tweeted in October. "He really took charge of his future."
That included giving himself a new last name: Michael (who, like four of his siblings, was adopted) legally changed his last name recently from Blosil to Bryan.
PEOPLE has learned the teen was estranged from his music-producer father and that the pair had not spoken for months.
"We've received notification from his attorney that his name was changed, so we've changed our documentation," L.A. County Coroner Assistant Chief Ed Winter says.
Osmond family members and sources would not discuss in detail the problems between Michael and his father, and Blosil declined to comment to PEOPLE on his son's death.
Osmond, who had visited Michael often in L.A., "is absolutely devastated," Dancing partner Jonathan Roberts tells PEOPLE, recalling how the singer visited her son during his stint in rehab. Says Roberts, "We'd stop our lessons so she could call. She would always make time for her kids. She is such a good mother."
Notes the family friend, "Marie knew Michael was troubled, but I don't think she ever thought he would take his life."
Reporting by JOEY BARTOLOMEO, KEN LEE, ELIZABETH LEONARD and MONICA RIZZO