That was why the Boston Bruins forward found himself back in Weymouth, Massachusetts, in August, not far from the house he grew up in, armed with personalized Bruins jerseys, armed with swag, with Blades the mascot by his side. They walked up to the window, greeted by 3-year-old Quinn Waters, who was ready and waiting to meet the player he would later deem his "best friend."
Coyle was there because Waters couldn't come to him, couldn't leave the house all summer, a result of a tumor on his brain stem commonly known as medulloblastoma. Waters had been diagnosed on Feb. 11, the day after his third birthday, after his parents and his sister had noticed him slowing down, his walking compromised, his temper flaring, his speech altered. Surgery had removed 95 percent of the tumor, according to his doctor, and had been followed by chemotherapy, months of hospitalizations and a stem cell transplant.
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Which left him house-bound, given the risk of infection.
But no longer. Waters -- nicknamed "The Mighty Quinn" -- made it to the beach at the end of September, and on Tuesday he will drop the ceremonial puck ahead of the Bruins game against the San Jose Sharks at TD Garden (7 p.m. ET; NESN, NBCSCA, NHL.TV) as part of Hockey Fights Cancer month.
The family has gotten good news lately, after his first scan off of treatment revealed no new disease, since the last MRI in June.
"That's the best possible news we could get," Quinn's mother, Tara Waters, said. "We're so lucky to get that news. He gets to be home for Christmas, and Halloween."
He is even scheduled to start school in January.
The Waters family -- with Tara a police officer and her husband Jarlath in the Carpenters Union -- was known throughout the community of Weymouth and that, combined with a social media presence, helped get the word out. But it was in June, after Waters was released from the hospital following his stem cell transplant, that the Quinndow opened for business.
Declan Houton of the band Devri Boston had rewritten the words to the song "The Mighty Quinn" to fit Waters, and he showed up to perform it outside the family's home. They thought it was a nice moment, a nice thing, but they had no idea what it would become.
"My brothers came to the window and had water balloon fights with him," Tara said. "They couldn't come into the house because we weren't sure if they had any germs. We had to limit everyone's exposure to him. And then a couple of the guys I work with happened to be in the area on their bikes -- and they were like, 'You think Quinn would like to see a couple motorcycles?'"
From there, it exploded.
"It kind of became a competition with people," Tara said, laughing. "But really, so many people just wanted to come and see him and make him smile.
"People just wanted to cheer him up. I think everyone can put themselves in the spot of either being a parent or an aunt or an uncle or a grandparent to a child that is suffering in this way. And it kept him occupied, it kept him socialized. It was literally the best thing people could have done, and they didn't even realize when they started it or even when they did these little things, what an impact it had."
Coyle had heard about Waters, through the talk in Weymouth, through his mother, who realized she worked with Tara Waters' mother, through social media. He had sent a message, "Just to say something and make sure they're in good spirits and all of that," as he put it.
Meanwhile, police officers began stopping by the Quinndow. Firefighters too. The Dropkick Murphys played for Quinn. Ambulances swung by.
It made isolation feel a little less isolating.
"When that started going around, that people were going to visit him, police officers and firefighters and all that, it's like, we should do something," Coyle said. "I know the B's had the same idea. So we ended up [visiting] and I think it was really cool.
"I'm from Weymouth and it's kind of like one of your own people, someone from your neighborhood is battling something. It's how the community comes together and rallies around that one person because they're struggling and it's how everyone picks him up. So you want to be part of that and help out and make your community a better place with better people. That's why you do it."
They brought gifts, including Nerf guns, and had a Nerf gun fight.
"They were just all smiles," Coyle said. "That's what you go there for, is to make sure people are having a good time and feeling good and feeling positive and just smiling."
This time, though, Waters is coming to visit Coyle, his favorite player.
"I'm sure he's really excited and maybe a little nervous," Coyle said. "I'm excited. I know I'm excited. And other guys have been asking, hearing about it. It's going to be really cool. It's just going to be a really cool moment."
Another moment in a summer full of them, for which his family is eternally grateful.
"You have no idea what next summer is going to look like," Tara said, tearing up. "But you can look back at this summer and you have some pretty good memories, some pretty fantastic memories of things your son got to do that were amazing -- and that [visit from Coyle] was one of them."
They are grateful too that they have found themselves with a platform, given the popularity of Quinn, to draw attention to the need for blood and platelet donations, because, as Tara said, "they literally kept Quinn alive."
The family is hosting a blood drive Dec. 21 in Weymouth.
"Get the word out there," Tara said. "We hate asking for more, but that's the best thing that they can give. People have emailed us, like where can we send money? Don't send money, please go donate your blood and your platelets."