But even so, Matt arrived with his mom and girlfriend, there to share in the moment.
"For his final treatment, we had a game the night before, so we didn't tell him, we just showed up, a group of us," said Matt Grzelcyk, who grew up a mile from the Garden, in Charlestown, a neighborhood in Boston. "He really appreciated that. Then he walked straight to work after."
The 72-year-old is about to hit a milestone this year, finally seeing the 27 years he worked at the old Boston Garden matched by 27 at TD Garden, as part of the crew that transitions the arena for different events. He has no plans to stop, which was part of why he opted to treat the cancer the way he did.
It had been discovered when John Grzelcyk's doctor determined his PSA (prostate specific antigen) levels were high, which can be a marker of prostate cancer. He was sent for an MRI, which led to a biopsy.
It was cancerous.
Grzelcyk was faced with three options: Since his prostate wasn't enlarged, he could have done nothing and seen how it progressed, he could have opted to have it removed or he could have gone for radiation. Given that he didn't want to be out of work or unable to care for his grandkids, Grzelcyk went the radiation route. The course would be 30 days, going to Massachusetts General Hospital -- a quick walk from TD Garden -- each day.
"[It took] about 15, 20 minutes," he said. "I'd come back to work. I worked after. Radiation is not like chemo, it's not as bad as chemo. It's still radiation, after about the third week, I got tired. I took a day here and there, but not during workdays. I took a day when there was nothing [no events] here."
It was a stressful time anyway, with John Grzelcyk also carrying the secret that his son was injured. Matt Grzelcyk had sustained a shoulder injury in January, something that wasn't confirmed until after the season had ended, when he went in for surgery. It meant that John was keeping his mouth shut on multiple fronts.
"There's people that have worse cancer than I have," John Grzelcyk said. "I don't want to say it's normal -- there's no such thing as normal cancer -- but kids out there, young kids that have cancer. Women that have breast cancer and stuff like that. My sister-in-law died of breast cancer when she was really young, she was about 40, 41. So it hits home with me there, and now it's hitting home with me.
"But I've lived for 72 years. Some of these kids get cancer when they're 8, 9, 7 years old. It breaks your heart. If I could swap with a kid and let him live the rest of my life and take his spot … But yeah, I just feel bad for them."
And so, he hadn't wanted anyone to know, not really. And almost no one did, until Matt Grzelcyk posted the video of his dad ringing the bell on his Instagram account. John Grzelcyk's phone started buzzing.
"I'm not surprised by it," Matt Grzelcyk said. "But pretty motivating just to see. He never wants to make it about him. He just didn't want to upset anyone. It was cool to see his strength."