"Why," this devout young Catholic from Freehold, N.J., kept asking himself, "aren't you becoming a priest?"
Then, on Sept. 26, 2015 - a day Philadelphia had been bracing for all year - he was working in Nebraska when he glanced at the little TV on his desk.
"I saw all these seminarians lined up on a staircase, awaiting the arrival of Pope Francis," Graebe remembered last week.
He watched wide-eyed as Francis ascended the chapel steps at the Archdiocese of Philadelphia's St. Charles Borromeo Seminary, he said, and even more intently as dozens of smiling young men in black cassocks gathered around the pope for a photograph.
"I was in the heart of my discernment," Graebe recalled, "still discerning the 'if' of a [religious] vocation as well as the 'where,' and right there I started to discern Philadelphia."
"If you do have a vocation," he said, "you're never quite able to shake it off."
The Archdiocese of Philadelphia can't say for sure that any "Francis effect" explains it, but it reports that one year after last year's papal visit, overall enrollment at its seminary is up 13 percent over 2015.
Forty-five men from 10 dioceses and four religious orders entered this fall, according to the seminary, bringing total enrollment to 160.
Divining any clear trend in those numbers proves elusive, however.
Last year, when Francis' impending visit to the World Meeting of Families here was still on the horizon, enrollment at St. Charles was up 20 percent over the previous year.
Despite Francis' visit, the number of men entering from within the archdiocese this year is 18 - two fewer than last year - but significantly better than the five or six men it typically saw in previous years.
"What we do know is that men are entering with tremendous optimism and excitement about the faith," said Bishop Timothy Senior, rector of St. Charles Seminary, "and some say they have been strengthened and encouraged by Pope Francis."
Francis' two-day visit last year to Philadelphia - which also took him to Independence Mall and Curran-Fromhold Correctional Facility, and drew hundreds of thousands to his Mass on the Benjamin Franklin Parkway - was never the sole reason any member of this year's entering class chose to become a priest.
Nonetheless, several report that Francis' visit or his sunny and compassionate outlook helped tip their decision to study for the priesthood.
"Beginning around 15 or 16, I began thinking about a vocation," said 18-year-old Rob Bollinger, who entered St. Charles last month as a first-year student in its college division.
Both appealed, but religious life "was a way of helping the poor in spirit," said Bollinger. "The more I thought about what college to go to, I knew I had to give St. Charles a shot or I'd always regret it."
His parents were supportive - he has an older brother at the seminary - but his friends were "pretty evenly divided" when he told them his decision.
"Some said 'that's great,' " recalled Bollinger, while others said " 'What do you want to do that for?' And a few poked fun at the sex abuse scandal."
But Francis' place at the head of the Catholic Church helped Bollinger look beyond such negativity.
"It's the man himself," he explained. "He gives a lot of hope for the future church - that it's not going to be shrinking but around for a long time and be important."
While the number of U.S. Catholics grew from 71.7 million in 2000 to 81.1 million last year, the number of active priests declined from 49,000 to 37,500, according to the Center for Applied Research on the Apostolate at Georgetown University. Much of that is attributed to death or retirement.
The number of parishes nationwide has declined (mostly through consolidations) from 19,236 to 17,337 during that time, and the number of parishes without a permanent priest jumped from 2,843 to 3,553, CARA reports.
The trends are not as drastic for the relatively dense Philadelphia archdiocese - which has 217 parishes in five counties - as they are for some vast, rural dioceses, said Senior.
But as the clergy supply diminishes, he says, "a different skill set is evolving" for future priests, who will need to collaborate with an ever more active laity. "He's got to be able to develop relationships."
The "cookie-cutter, one-size-fits all" approach to seminary training that Senior encountered at St. Charles in the 1970s and '80s has given way, he said, to a "more personalized approach" built around each man's strengths and limitations.
For men entering at the college freshman level, preparation for ordination typically takes nine years, according to Senior, but they may enter at any grade level or attend retreats to help them determine whether seminary life appeals. Those who have completed their bachelor's may enter straight into the theology, or graduate, division, as Graebe did.
The retreats - and Pope Francis - helped 18-year-old Gabe Fairorth find his way to St. Charles this year.
"In my junior year" at Berwyn's Conestoga High School, he found himself "absolutely terrified" when his "very college-oriented" guidance counselor "sat me down and asked 'What next?' "
"I had no answer," Fairorth recalled last week as he sat with Graebe and Bollinger. When people told him he'd make a good priest "I used to brush it under the rug," he said, but now, he discovered "it had been working in the back of my mind."
He began reading about seminary and the priesthood and took part in a St. Charles-sponsored retreat in Lancaster. What resonated, he said, "was the idea of working with people and fighting for the souls of your parishioners, for their salvation.
"This idea of being in a sense a 'spiritual doctor' became very appealing," said Fairorth.
When he was younger he had "not been a big Francis fan," he said, and "loved" Pope John Paul II, whom he called his hero.
But when he made the trip into Philadelphia last year to see Pope Francis celebrate Mass on the Parkway "and I saw how drawn everybody was to him when he spoke, that was the first time I felt peace about the priesthood."