"Sometimes he feels so blessed that it happened to him and not one of the grandkids, then he's upset with himself for not knowing the water was that bad," the man's mother tells PEOPLE

A family beach day has turned into a horrific nightmare for one Texas man.

Brian Parrott, 50, had part of his right leg amputated in an attempt to save his life from a deadly infection from “flesh-eating” bacteria he contracted after a trip to the beach in Galveston on June 12.

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The security guard was enjoying a day at the beach with his grandchildren and three children – Brian, 26, Stefanie, 24, and Cody, 17.

Parrott s mother, Donna Dailey, 68, tells PEOPLE her son became ill the day after he returned home from the beach. A couple days later, he noticed a rash and boils on his leg and went to the hospital, where part of his leg was amputated – five days after his trip to Galveston.

Parrott is currently being monitored at Lyndon B. Johnson Hospital in Houston. A second surgery was performed to flush the rest of the limb out with antibiotics to avoid further infection.

“Doctors hope [the infection] is controlled, and they’re watching it real close,” Dailey tells PEOPLE. “Every time it seems like it’s getting better, then something else happens.”

Dailey says doctors haven’t given an exact name of the infection, but they did call it a “flesh-eating disease” and believe he likely contracted it through a scratch on his foot.

Due to privacy laws, the hospital was unable to confirm Parrott s condition to PEOPLE, but Diana Martinez, epidemiology program manage for Harris County Public Health, said that her office had opened an investigation into a reported case of Vibrio involving a middle-aged man who was exposed to saltwater, according to the Houston Chronicle.

According to the Galveston Health Department, the rare flesh-eating bacteria Vibrio vulnificus lives in coastal waters and can cause infection when an open wound is exposed to brackish or salt water.

If an open wound is exposed to untreated water, the area should immediately be washed with soap and fresh water.

Vibrio can also be contracted from eating raw or undercooked shellfish. This form of the illness is called Vibrio diarrheal and most people recover without treatment. However, some people may become sick enough to need extra fluids, antibiotics and possible hospitalization.

The CDC estimates that there are 95 Vibrio vulnificus cases each year in the U.S., including 85 hospitalizations and 35 deaths.

Most at risk for severe illness and death from Vibrio vulnificus are people with a weakened immune system. Mild symptoms include diarrhea, vomiting and abdominal pain. More severe symptoms include sudden chills, fever, shock and skin lesions.

Several beaches in Galveston were under an advisory for elevated bacteria levels on Thursday. When an advisory is put into place, samples are tested daily until the bacteria levels return to normal. A beach advisory does not mean it is closed, but it is “simply to inform the public of the elevated bacteria level so people can make an informed choice about swimming in the affected waters,” the Galveston County Health District says on their Beach Watch Program website.

Dailey says her son’s emotions have been a “rollercoaster.”

“Sometimes he feels so blessed that it happened to him and not one of the grandkids, then he’s upset with himself for not knowing the water was that bad,” she says.

The family says there were no warning signs that the bacteria was in the water, and they want to warn others.

“You don’t think about it. You know that the water isn’t totally clean, but you don’t think you’re going to lose a limb,” Dailey says. “You definitely don’t think it’s going to happen to you or your family members.”