For decades after, John had shepherded his parents to his brother's final resting place in North Philadelphia, each time squiring them to the marker of tragedy.
Last week, DeVos rooted around in the dirt, mildly obsessed. He had to find the grave. It was his familial duty.
His memories are vague before that day in October 1948 when Michel DeVos was struck by a train on tracks near his house. John was 7.
The middle of three blond-haired, blue-eyed boys whose parents had just brought them to Philadelphia from Calais, John DeVos had heard that the French port on the English Channel had been so battered during World War II that they had to leave.
"The front of our house was blown away," he said.
In January 1947, Paul DeVos moved his wife, Renee, and the boys to the United States, found a job at North American Lace Co., and moved into a two-story rowhouse on the 200 block of East Tioga Street.
Though none of them had spoken English in France, Michel, then 10, was a quick study. He deciphered bills and translated for his mother. He also kept his rambunctious little brothers, John and Denis, out of street fights.
"He took care of us," DeVos said.
But in October 1948 came terrible news. Michel had been playing on the tracks a few blocks away.
"I remember running up to my room and crying when I found out he had been hit by a train," DeVos said.
An acquaintance donated a plot at Greenmount. There was snow on the ground and a Cub Scout troop at the burial.
At home, Renee DeVos filled the house with pictures of Michel. And she insisted that John take flowers to his brother's grave. Thus began a one-mile walk, every Sunday after church, until the family moved in 1956.
John, a slight boy, would walk two blocks to 3300 N. Front St., where he picked up the flowers. He would then cross a bridge over the tracks where Michel had died. He would pass a hospital where, from behind barred windows, men in robes would peer at the street below.
At 4301 N. Front, he would hook a right into Greenmount, pass the office, and continue past gravestones lined as tightly as rowhouses.
"My mother wouldn't come up with me," DeVos said, "because she would break down."
At the intersection of a gravel road and a dirt one, he would find a small bush. From there, 20 paces toward a tree, rested a granite slab:
"MICHEL DEVOS - 1937-1948."
Visits became infrequent after his parents moved to Bensalem and then North Carolina. Renee DeVos was busy, too, having borne four more children. But John's memories continued to serve as a beacon for them all.
In 1976, his father came up to visit and asked, "Would you take me to the cemetery?" Paul DeVos had gone himself but not found the grave. He had been told at the office that there was no record of Michel.
"I found it," DeVos recalled. That was that.
In 1999, his mother made the same request, the year before she died.
"She was so grateful that I found it for her," he recalled. "She was filling up" with emotion.
A year ago, DeVos pulled into Greenmount for the first time since 1999. But he could not find Michel's grave. Confused, he left.
A few weeks ago, he returned. Again, no luck. Office staff told him there was no record of his brother's name in the alphabetized card file of those buried at the cemetery.
So DeVos, a retired mechanic, returned a week later with a 10-inch screwdriver and a small spade.
"You just be careful that you don't end up in jail," his wife, Alice, warned.
He pricked the soil, gingerly probing for answers.
"I hit some rocks." He scooped out patches of dirt, finding two flat markers just below the surface.
"I'm on to something now," he thought.
On April 11, he returned. After 15 minutes, the screwdriver hit something hard.
DeVos cleared dirt like sand with a clamshell. Ten inches deep, he saw three letters: "DEV."
Soon after: "MICHEL DEVOS."
"I was so happy," he said. "Like I found a $20 gold piece."
And yet, he was unsettled. Greenmount was no potter's field. Weren't graves to be maintained in perpetuity?
When he learned of DeVos' experience, cemetery owner Joel Winston was concerned and vowed to look for answers.
He found that Michel's name had never been logged in the card directory of the deceased. Had the family known the plot owner's name - Ludwig Kaufman - a cross-reference would have found Michel among the six buried in Kaufman's plot.
A 30-year employee, though, found a large ledger no one else knew existed. In it were names dating to 1878 - including that of Michel DeVos.
Winston said he would look into the other sunken markers, too. Apparently, Michel's had been pulled down by the weight of its concrete foundation.
"This is a normal thing that happens in any cemetery," he said.
He sent crews to scrub and reset the marker: "We took it out, we washed it down, put a new foundation in."
On Thursday, John DeVos parked his black Dodge Caravan near the bush at Greenmount and darted toward a strip of freshly packed dirt.
"What did they do - bring it up?" he asked. "I was looking for a hole. I had brought a jug of water to clean it off. This is great, though."
Maybe, he said, it was time to move Michel's grave to the cemetery in Northeast Philadelphia where his parents were laid to rest. Maybe, in other words, it was time for John to bring them together one last time.