DRACUT — When Scott Middlemiss crossed the finish line with his young son Jack, it became an iconic moment of last year's Boston Marathon.

When he runs again this year, he'll have a team of 10 running with him for the Joseph Middlemiss Big Heart Foundation, thanks to a special partnership with Marathon Director Dave McGillivray.

Last year, McGillivray came to Westford's Abbot Elementary School, where Middlemiss is assistant principal. Upon seeing how riveted the students were listening to McGillivray share his story of failure, persistence and success in running, teacher Nancy Feehrer had an idea.

She knew McGillivray had co-authored a memoir called "The Last Pick," which traces his experiences from being the short kid who was always picked last for sports teams to an accomplished athlete whose vast repertoire includes 145 marathons.

"But I thought that he needed a children's picture book so that these kids could read about and be inspired by his story now -- not when they're old enough to read his book intended for adults," Feehrer said.

With the help of Middlemiss, she reached out to McGillivray and the two collaborated on the book. "Dream Big,'" illustrated by Ron Himler, is due to be published by Nomad Press next February.

Nine of the 11 runners for the Joseph Middlemiss Big Heart Foundation will raise money to provide copies of the books to schools around the state for inspirational talks Middlemiss and McGillivray will give each month for a year after its release.

"The whole idea is to tell the kids to never underestimate their own ability to set goals and not limits," McGillivray said.

Scott and Kate Middlemiss started the foundation following the 2013 death of their 6-year-old son Joseph due to complications of cardiomyopathy, a condition that causes an enlarged heart. Jack, 3, was also born with cardiomyopathy and needs a heart transplant. Their daughter Grace, who is 18 months old, does not have the condition.

The foundation's mission is to raise funds for cardiomyopathy research, support families with children with the condition and spread Joseph's message about the power of kindness.

McGillivray became familiar with the Middlemisses when Kate was a teacher in North Andover and had one of his children in her kindergarten class. When Joseph died and the Middlemisses created the foundation, McGillivray and his family took an interest in supporting the organization's work.

Last year, that included providing a Boston Marathon bib to Scott to raise money for the foundation. He also gave Jack his own medal for finishing the race with his dad.

McGillivray has had his own heart challenges. Despite his athleticism, a few years ago he was diagnosed with severe coronary artery disease.

"There's definitely some synergy between everything they've been through and some of my personal experiences," McGillivray said.

"It was natural to tie all of this together."

In better health now, McGillivray said this year will be his 45th Boston Marathon. He will run for another cause: the Martin Richard Foundation, named for the boy killed in the 2013 Marathon bombing.

Initially, Dracut firefighter Justin George was going to be the sole runner for the Middlemiss foundation this year.

George, who rose to local prominence in October when he worked with other volunteers to find a missing Dracut woman, was one of the first responders at the Middlemiss home the day Joseph died. Scott stayed home to take care of Jack, who was an infant at the time. George sat at the hospital with Kate for hours before family arrived, keeping her company on the worst day of her life.

George felt defeated that he couldn't do more to save Joseph. But to Kate, he was her hero.

Kate didn't know who he was at the time. She was grateful when he reached out to her on Facebook several weeks later.

"I was able to tell him how appreciative I was, for going above and beyond the call of his job for me," Kate said.

Since then, George has become involved in the foundation and the two families became close friends.

When George, an active member of the Army National Guard, was deployed to Afghanistan for 10 months, the Middlemisses delivered a meal to his wife and children each week he was away.

Though he's not a runner -- he actually hates running, he said -- George jumped at the opportunity to run in Joseph's honor. 

"This is what I can do now for that day," he said.

Scott hadn't planned to run again this year, but then McGillivray offered him a bib.

"I wasn't prepared, but you can't really say no to the director of the Boston Marathon," Scott said.

Jack plans on finishing with him and "winning the marathon again," he said.

To donate to the runners, visit firstgiving.com/jmbigheart/fundraisers.