Family Searches for 'Amazing' and 'Irreplaceable' Mom Missing in Okla. After Brain Surgery

Dawn Sherrill
Dawn Sherrill

Oklahoma City Metro Search and Rescue Dawn Sherrill

The search is continuing for an Oklahoma woman who recently underwent brain cancer surgery and was last seen driving off from her house in her boyfriend's red pickup truck on Wednesday, July 21, according to ABC affiliate KOCO.

Family members told NBC affiliate KFOR that Dawn Sherrill, 55, was possibly disoriented, and authorities said she left behind her cellphone and wallet, according to KOCO.

"My mom is an amazing person. She's absolutely irreplaceable," her son, Dylan Sherrill, said.

At the end of June, doctors discovered multiple masses on her brain; one was removed, while the other was inoperable, Dylan told KFOR.

Caddo County Sheriff Spencer Davis, whose office has been searching for Dawn, told the outlet, "She's not in her right mind right now. With her condition, we don't take this lightly."

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Dawn Sherrill truck
Dawn Sherrill truck

Oklahoma City Metro Search and Rescue

On Wednesday night, members of Sherrill's family met with the Oklahoma City Metro Search and Rescue Team to plan a search over a 50 miles on Saturday.

"I'm beyond myself. I'm almost to where I can't feel anything, I can't think, I can't process. For her to be out there possibly alone, scared or even if someone has her and is just not telling us, it is just terrifying," Dylan told News 9.

"All the different thoughts that run through your head," he says, "and all the different scenarios that could happen."

PEOPLE was unable to reach Dylan, and a message left for Caddo County Sheriff Spencer Davis was not immediately returned.