Khattiya; daughter of Lt Gen Khattiya Sawasdipol said her father is critically injured and is in a coma.
"If he does not pull through, I will decide later what should be done next," she told reporters after visiting her father at Hua Chiew Hospital.
Outpoken red shirt leader Lt Gen Khattiya is shot and suffered a serious wound at the base of the head on Thursday.
He was reportedly being treated in intensive care unit at Hua Chiew Hospital. At 8.20pm, Seh Daeng is undergoing a CAT scan.
Reports said that he was shot in the head near Sala Daeng intersection while he was giving an interview to a Japanese reporter.
A Nation reporter at the hospital reported that he saw Seh Daeng being moved from ICU room to a CAT scan room. His head was covered with bandage and wearing an oxygen mask.
The incident happened shortly after the government sealed off the roads surrounding the rally site, shut off electricity, cut off water supply and all transportation around the site.
Reporters at the scene reported that they heard what they believed were bomb explosions and gunfires.
Nation television channel reported that an unknown number of people were injured from the explosions and are sent to a nearby hospital.