He will be sentenced in 3rd District Court in late September.
"We're still struggling every day," said Ryan Pack, the father of 18-month-old Colum Pack who died in the collision on Christmas Eve 2011. "It doesn't make that easier, but it was good to hear him say sorry."
According to prosecutors, Ainsworth was driving his Chevrolet Suburban west on 9000 South on Dec. 24, 2011, while high on methamphetamine and THC. He dropped his cellphone, went to reach for it and lost control of his vehicle.
The Suburban jumped the center median near 1000 West and clipped an oncoming Nissan Altima. Seconds later, the SUV hit an oncoming Subaru Outback head-on, killing Colum and severely injuring his 3-year-old brother, Finn, and their parents, Ryan and Raquel Pack.
Ainsworth, who appeared before Judge Deno Himonas in a wheelchair, also was injured in the collision.
On Friday, as the judge outlined the details of his plea agreement, Ainsworth rocked the wheelchair back and forth.
"I am guilty, sir," Ainsworth said to the judge. "And to the Pack family, I am so, so sorry."
He looked over at the mother and father as bailiffs wheeled him out of the courtroom, his long, white beard framing the contours of his mouth and crinkles of his eyes as he searched theirs.
Had they forgiven him?
"We're trying," Raquel Pack said after. "We're glad he finally accepted responsibility."