Michael had grown estranged from his father in recent years to the point he had petitioned to legally change his last name from "Blosil" to "Bryan."
"My relationship with my father while I lived at [home] was extremely strained," Michael wrote in an Aug. 28, 2009, petition for a name change with the Utah Country Court. "At the present time, I have no relationship with my father and have no desire to continue to carry his last name."
His request was granted on March 1 and his death certificate refers to him as "Michael Bryan."
The reason for the estrangement isn't immediately known; Blosil, reached by phone by PEOPLE, declined to comment, and a rep for Osmond also didn't comment.
Michael wasn't the only Osmond sibling to have a troubled relationship with Blosil, whom Osmond divorced in 2007 after 20 years of marriage, with Osmond getting sole custody and visitation rights for Blosil.
Osmond's 22-year-old daughter Jessica applied to drop "Blosil" – and take the name of "Osmond" – in a motion filed in January with the same Utah County court.
"While I lived with my parents, my relationship with my father, Brian Blosil, was extremely strained," she wrote in her name change affidavit. "At the present time, I have no relationship with my father and have no desire to continue to carry his last name. ... I wish to be known by my mother's surname, Osmond."
She was granted the name change on March 5, one week after Michael's death.
Another of Marie's seven surviving children, Rachael Blosil, 20, spoke of their father during the funeral service for Michael, held at the Church of Jesus Christ of Latter-day Saints Chapel in Provo, Utah.
"A couple of years ago I asked Michael to give me away at my wedding," she told mourners. "For those of you who don't know the situation, my father and I don't get along too well, so I figured since [Michael] knew me the best, he should have that right."