Tejano singer Emilio Navaira [ tickets ], 45, suffered critical head injuries just before dawn March 23 when his tour bus crashed into an interchange barrier on a Houston-area freeway, propelling him through the windshield, according to the Associated Press. The performer, who was driving at the time of the accident, underwent a two-hour surgery to remove a blood clot that was putting pressure on his brain. His doctors have warned his family that the performer "might not make it," even though he survived the operation.

Following the surgery, Navaira's doctors entered him in research project that uses hypothermia to keep his brain from further swelling and aid his recovery. If Navaira survives, the possible lasting repercussions of his injury could leave the performer in a persistent coma or a vegetative state. He also could face weakness, paralysis, difficulty speaking or memory loss, among other effects of his injury. He remains in critical condition at Memorial Hermann Hospital in Houston.

Police reportedly said the crash remained under investigation but the preliminary probe showed Navaira was not licensed to drive the 26,000-pound tour bus. The singer's blood will be tested for alcohol but the results wouldn't be known for a couple of weeks. Officials said there was no sign of drinking on the bus, adding that the Grammy-award winning singer may have fallen asleep at the wheel.

The five other people on the bus--all but one of them band members--suffered various injuries but none as critical as Navaira. Of those hurt, bass player Rick Vega remained hospitalized yesterday (3/24) with undetermined abdominal injuries. The others, including Navaira's brother, Raul, who sings in the band, were treated for cuts and bruises and did not need hospitalization.

At the time of the accident, Navaira and his band, Rio, were driving to San Antonio after playing a club show in the Houston-area. Navaira--known to fans simply as Emilio--and Rio were scheduled to head to California for tour dates later this week.