ST. JOHNS COUNTY, Fla. -- Joe and Heidi Linebach of Putnam County were near Matanzas Inlet on Sunday afternoon.

"Heidi and I were walking on the beach. My wife likes to collect shells," Joe Linebach said.

Toward the end of their walk, they heard screaming from the water.

"Heidi spotted two heads floating in the water," Linebach recalled.

They were two little boys.

According to the St. Johns County Sheriff's Office, they were eight and nine years old.

So Linebach, 55, jumped into the waves to save two children.

"The boys. That's all I thought I had to worry about was the two boys," he said.

But he was wrong.

"I finally got to the two boys and that's when I noticed their dad was floating face down and they were using their dad as a life preserver," Linebach said.

"Oh they were screaming, screaming 'he's dead! He's dead! He's dead!'"

Linebach doesn't remember much more about being in the water.

"I don't know how I got back. I don't know if I pulled their dad and they came along with them ... because they would not let go of him," Linebach explained.

Once on land, the man -- Lupe Cortez, 32, of Deland -- wasn't breathing.

Linebach and his wife did chest compressions.

"And then finally you could feel air come in and out of his lungs," Linebach stated. "We definitely had some hope he was going to make it."

Rescue personnel arrived at the scene. The children were okay, but Cortez was rushed to the hospital. A sheriff's report said Cortez had two cardiac arrests while en route and was in critical condition.

Some witnesses said the rip currents were strong that day, but Linebach admits to not feeling them.

Linebach's instinct and strong swimming saved the two children in the waves. Now he and his wife hope they can help save the boys' dad in the best way they know how.

"We're keeping him in our prayers. Heidi's put the whole incident on Facebook and asked all her friend to pray for this man," Linebach said, "so he can come out of this and be with his kids."