He ran to the living room, where he found his mother dying.
"She took her last breaths in my nephew's arms," Morris told Fox 2.
Dorsey’s oldest child, a college-age daughter, was not home when the slaying took place.
Dorsey's ex-boyfriend, Earl Maxwell, was named a "person of interest" in the shooting and was taken into custody on Tuesday, according to Fox 2. It was not immediately clear Wednesday morning if he had been charged.
Morris told Fox 2 that her sister had moved on from the relationship, but that Maxwell, 38, couldn’t let go. Relatives told WXYZ that Maxwell threatened Dorsey just days before she was killed.
Maxwell allegedly told others that if he could not get in touch with Dorsey, he would shoot her in the head, WXYZ reported.
The sisters’ elderly father, James Morris, is heartbroken over his daughter’s death.
"I had three daughters, I had three beautiful daughters, and he put a hole in my heart," James Morris, 72, told Fox 2.
Megan Morris told the news station that the day her sister was slain made her death even more devastating for the family.
"His daughters are all he has," Morris said of her father. "For him to get this call on Father's Day, the one day where he's supposed to be celebrating with his girls. He gets a call saying this coward ripped his life from him."