New family crisis takes heavy toll on DONNY OSMOND in the wake of sister MARIE‘s tragedy.

Donny Osmond faced a frantic family crisis recently as his infant grandchild nearly died, The ENQUIRER has learned exclusively.

As the life-or-death drama unfolded, Donny flew from Las Vegas – where he’s been watching over his distraught sister Marie – to Utah, where his third grandchild was struggling to stay alive.

Donny’s son, photographer Brandon Osmond, called his father in a panic because his wife Shelby was having difficulty with her pregnancy in mid-June.

On three separate occasions, Shelby was rushed to the Alta View Hospital in Sandy, Utah, suffering from severe labor pains. She was sent home the first two times after the pain eased and labor stopped progressing.

But the third time, Brandon – worried about the slow progress and his wife’s intense pain – insisted that she stay in the hospital.

"Brandon’s voice was trembling with fear," said a family insider. "He called his dad and told him, ‘The baby’s not coming out like it should – please get here fast.’"

Donny, who performs in a Las Vegas production with Marie, immediately flew to Utah, although he was worried to leave his sister, even for a short time.

Marie has been deeply distraught since her son Michael leapt to his death in Los Angeles in February.

As The ENQUIRER has reported, the Osmond family has been so concerned about her mental health, they’ve considered having her leave the show to get treatment at a mental hospital.

"His grandson was in trouble, so Donny had to go," said the insider. "He was feeling the pressure of being pulled in both directions – and trying his best to help out."

At midnight on June 18, little Daxton Michael Osmond was born, but he was having problems breathing. The infant was taken to the neonatal intensive care unit as the Osmonds prayed for him to pull through.

After three nights, the baby began to nurse and breathe properly, and was able to go home.

Throughout the crisis, Donny shuttled back and forth on planes between his grandson’s bedside and Marie in Vegas.

Little Daxton is now expected to make a full recovery, and Marie has also been doing better recently