A suburban New York man faces up to 21 years in prison for allowing his unlicensed 15-year-old daughter to drive an SUV that crashed in northeastern Pennsylvania last summer, killing three of her friends.

Michael Ware, 54, of Scarsdale, is scheduled to be sentenced Thursday in Wayne County Court. He pleaded guilty last month to three counts of involuntary manslaughter and reckless endangerment in the Aug. 30, 2014, crash.

Prosecutors say Ware gave the keys of his Chevrolet Suburban to his daughter, who drove five friends to breakfast before losing control of the SUV and flipping it in Paupack Township, in the Pocono Mountains.

The crash killed Ryan Lesher, Shamus Digney and Cullen Keffer, all 15-year-old sophomores at Council Rock High School in suburban Philadelphia. Three others were hurt.

Victims' family members on Thursday called for a stiff sentence for Ware.

"He basically gave his daughter a gun and put the bullets in it for her," said Wilson Black, Shamus' uncle.

The teenage driver acknowledged responsibility in juvenile court to vehicular homicide counts and was placed on indefinite probation. She also was ordered to do 300 hours of community service, pay restitution and write a 2,000-word essay on the impact of her crime.

Her attorney, John Stieh, told The Philadelphia Inquirer in May that she was in a "really dark and nasty place" and "doesn't stop thinking about it." He said she hadn't spoken to her father since the crash.

Michael Ware told reporters after his July guilty plea that he was "sorry, very sorry."

The charges carry a maximum of more than two decades in prison, but Ware is likely to get far less time under state sentencing guidelines.