Dracut Father Running Boston Marathon For Son In Need Of Heart Transplant

DRACUT (CBS) – Running is always personal.

Scott Middlemiss will run on Marathon Monday for the Joseph Middlemiss Big Heart Foundation, the organization he created in memory of his young son who he lost to cardiomyopathy.

There is nothing closer to his heart.

This is Scott's second Boston Marathon, and this time he has some new inspiration.

Two-year old Jack Middlemiss is the heart of his family, and it's clear he is also the soul.

Seven-month-old Grace delights in her brother Jack's dance moves.

Grace is perfectly healthy, but her big brother is not as lucky.

Despite his big smile and big personality, Jack is facing a huge battle - he needs a new heart.

Jack has hypertrophic cardiomyopathy and is waiting for a transplant. His big brother Joseph died at the age of six from cardiomyopathy, when Jack was just one month old.

"I was obviously not in a good place; I was in a funk", says Scott. "Everyone said 'You have to do something active; you have to do something to get your mind right.'"

After losing Joseph, his family could have given up. But Joseph's parents wanted his death to mean something.

So they started the Joseph Middlemiss Big Heart Foundation, where the motto is "All you need is love."

"It gives us an outlet of hope," says Scott's wife, Kate Middlemiss. "It allows us to carry on, not only our son's memory, but also his legacy; what he taught us in his six years."

So Scott will run his second Boston for the Big Heart Foundation. But Jack knows the real inspiration..

"Who does Daddy run for?," Kate asks Jack, prompting a response of "Me!"

When Kate asks Jack who else his dad runs for, he's got an answer for that as well.

"Joe Joe," he beams.

This year, the Big Heart Foundation has a team of two runners. Laura Ray-Hokanson knew she just had to support the mission.

"The pay it forward mentality that is behind the Big Heart Foundation is really what the world needs more of," said Ray-Hokanson.

They run for the foundation's simple goals of spreading kindness and cheer, funding music scholarships for kids, and supporting other cardiomyopathy families.

It's an inspirational cause for a man who now seems to find hope everywhere he looks -- especially along the Marathon course.

"It's so inspiring  -- some of the people, and that's what I'm looking forward to again," Scott said.