BOSTON (CBS) – The Boston Marathon is more than just a race. It brings people together to test their endurance on the course and a community’s commitment to helping others in need.

Trainer Rob Vasquez is running the marathon for FamilyAid Boston, a non-profit providing solutions for family homelessness in Greater Boston.

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“You’re running for a cause; you’re running for a purpose,” Rob said. “You’re running for somebody. You’re running for a community.”

Rob was introduced to the charity through his training client, Jim Partridge of Newton. The pair became close when Rob kept pushing Jim to go harder, faster and stronger in his workouts. And Jim did just that.

Jim Partridge and Rob Vasquez have developed a friendship that includes Rob running this year’s Boston Marathon in Jim’s place. (WBZ-TV)

“He was one of the most high-energy, motivational at the gym. As well as in life,” Jim told WBZ.

Rob says their relationship means a lot to him. “That grew into a great friendship. That grew into I would do anything for him.”

Jim had run the Boston Marathon once before for FamilyAid Boston in 2013 and wanted to do it again. However, a diagnosis of cancer has put that goal on hold. Instead, Rob will run for Jim.

“It’s really,” Jim paused and blinked back tears. “Sorry. It’s very emotional. It’s special to see someone so dear to me experience the joy that I was able to experience.”

And Jim says he will be at the Mile 17 marker to give his friend a big hug and motivation to keep going.

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“I’m not a big crier, but that’s going to be the point,” said Rob.

Khanisha Felder and her daughter Serenity slept in a car most nights before the help of FamilyAid Boston. (WBZ-TV)

And their efforts in the marathon are benefitting families who really need help, like Khanisha Felder and her daughter Serenity, of Dorchester. Khanisha says she and Serenity were sleeping in a car most nights before the help of FamilyAid Boston.

“I remember having to go into the Dunkin Donuts to wash up. Wash her up and change her clothes in a Dunkin Donuts.”

This despite Khanisha having a job. She still struggled to afford housing.

“When we used to sleep in the car, it was very scary. And just being out by myself. It was very scary.”

But, things have improved greatly in the past year for this mother and daughter, thanks to FamilyAid Boston.

“I’m able to cook my own meals. I’m able to shower. I’m just able to feel comfortable and happy and safe.”

And November will be a happy month for Khanisha and Serenity as they mark the one-year anniversary of living in their own apartment.

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You can donate to FamilyAid Boston through the Boston Marathon donation site, https://www.givengain.com/cc/familyaidboston/.

Breana Pitts