SAN DIMAS, Calif. (KABC) -- Cash Hennessy has played sports since he was four years old.
"He's an athlete through and through. He cares about his athletics. He's a competitive kid," said his dad, Chad Hennessy.
Cash is now 13 and has lived a pretty normal, active life, but that all changed last weekend.
During a football game in Rancho Cucamonga on Sept. 17, Cash told his parents on the field he couldn't breathe.
His mother, Brenda Hennessy, said their lives were flipped upside down as he collapsed on the sidelines. They say their son was having a heart attack.
Luckily, Chad said several medics who were in the stands at that moment rushed in to help and start CPR immediately.
"Having those medics there was so key because there was a AED or defibrillator on the site, but from what I heard since then is that it didn't have batteries in it," Chad said.
Cash was rushed to Children's Health Orange County where doctors discovered he was born with a congenital heart condition.
Since then, he's had open heart surgery.
"He's on a ventilator," said Cash's mom. "They're trying to regulate his blood pressure. It's expected and the next steps are neurology, but today is a good day."
Since then, the community and some of the biggest names in sports have rallied behind Cash.
In a video, Golden State Warriors star Klay Thompson sent his best wishes to Cash saying, "You have so much greatness ahead of you. Just keep your faith, keep your head high, keep saying your prayers and just lean on your family during this time."
Los Angeles Dodgers broadcaster Jose Mota also sent Cash a video message saying, "Never lose hope, ok? Here in the Dodger family, we love you and we wish you the very, very best. You are in God's hands my friend."
Cash's dad said it's all overwhelming.
"That level of support and that level of rally has just been fantastic," he said.
Cash's parents said the boy has not been able to see those messages just yet, but they can all imagine how excited he's going to be to see some of his sports heroes wishing him well.
Moving forward, Cash's family plans to advocate for health screenings and early detection in youth sports and wants to make sure there's always at least one person who knows how to CPR at all games.