"The day he died, my grandson who died with him stayed with him all day," Baker said.
The father was mowing the lawn earlier in the day as Daniel Hykes followed along with a toy mower, she said.
Pennsylvania State Police said the father and son were stopped at the intersection facing west on Pa. 16 when Hykes' 1991 Ford Escort was hit from behind by a westbound 1988 Chevy van driven by Thomas Arthur Potter, 57, of Greencastle. The report said the impact forced the Escort into the eastbound lane, where it collided with a 1995 Nissan Pathfinder driven by Robert Ernest Branco, 48, of Dumfries, Va.
The second impact sent the Escort into a 1972 pickup driven by Robert J. Woodward, 42, of Mercersburg, which was sitting at the stop sign on Hill Road, according to police.
Potter was treated and released from Washington County Hospital, according to police. Branco suffered minor injuries and was released from Waynesboro Hospital, the report said.
Woodward was not hurt, police said.
Peiffer said Mark and Daniel Hykes were wearing seat belts, but "there was a tremendous impact on that car" from the larger Pathfinder.
Jennifer Hykes said her husband and son had driven to the store to buy a newspaper.
The investigating officer, Trooper Randy Kane, said no charges had been filed Sunday night and the accident was still under investigation.
"Mark was a fine young Christian man ... It was known to everyone," the Rev. J. Herman Fisler said Sunday evening of Hykes, who was the Sunday School treasurer and head usher at the Grace Bible Church.
"We really just committed the service to reflect on him and his life and that of Daniel," Fisler said. He said members of the congregation came forward and spoke about the father and son, or about similar losses they suffered in their lives.
"Other than your faith in the Lord, there is no preparation for this," Fisler said.