"Right now we're just asking everyone to please pray for Gabe and our family," he said. "We're trying to keep our faith as strong as possible."
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Marshall also posted the update in a Facebook group called "Prayers For Gabe Marshall."
"It's a roller coaster," Josh Marshall told KWCH. "You go from feeling perfectly fine and normal, and then just the fears of what's going to happen. The not knowing is what really hurts."
Marshall is trying to keep things in perspective because of his son.
"He is my superhero," Marshall said. "He has (shown) me what life really is about and how to cherish the most out of everything."
In March, Gabe's dad set up a GoFundMe page to help with medical and financial needs. It has raised over $9,000 of its $15,000 goal.