63-year old Phillip Grigg is in a medically induced coma battling infection Arpaio said.
"I'm really concerned about his condition and he needs a lot of prayers, this is serious," said Arpaio Monday afternoon.
On New Year's Eve, Grigg jumped into action to assist Phoenix Officer Scott Sefranka.
Both men were in a scuffle with robbery suspects outside a pharmacy when one of the men got a hold of Sefranka's gun and shot the officer and Grigg.
"He's (Grigg) still in critical condition so we're all praying for him," said Arpaio.
Sefranka is out of the hospital.
Arpaio told ABC15 he has another concern regarding Grigg's family's financial situation.
"It's the type of situation when you talk about benefits, no man's land when you really look at it, we're trying to do everything we can to get money to the family," said Arpaio. "He's been in ICU for 45 days, the bills add up."
Arpaio told ABC15 people have stepped up to help.
"We've given them $15,000 from our MCSO memorial fund, which comes from donations and 100% of the money in that fund goes to those in situations like Grigg's and others from MCSO," said Arpaio. "A Posse in Fountain Hills was nice enough to donate another $1,000 to Phil and his family."
Arpaio has not visited Grigg lately, due to Grigg's health, few visitors are allowed.
"A week ago he looked good, then here we go again, it looks bad, it's back and forth, back and forth," said Arpaio.
The Sheriff said he appreciated the Phoenix Police Department for expressing appreciation and support for Grigg and hopes others in the community would as well.
"He (Grigg) is a hero and I will do everything I can to help him and protect my Posse members who all go out there to help the community, these are volunteers, they have to buy all their stuff," said Arpaio.
If you would like to donate to the Sheriff's Memorial Fund click here .