But he added, "While the majority of adults and children with epilepsy live with their seizures well-controlled and can live up to their full human potential, there are rare, tragic cases of sudden, unexplained death in epilepsy [SUDEP] ... even well-controlled seizures sometimes break through, especially with forgetting to take medication, with excessive alcohol or sleep loss, or a serious second illness, such as a very bad flu or pneumonia."
Regardless of the cause, Travolta's attorney Ossi said that the family is now grieving. He added that the incident "is the worst pain any parent can experience, the loss of child."
Speaking for Travolta, Ossi said, "This is the worst day of his life."
In multiple interviews, Travolta and Preston have always attributed their son's illness to carpet-cleaning products they once used in the house.
"It was about seven years ago, and I was obsessive about cleaning -- his space being clean, so we constantly had the carpets cleaned," Travolta told Larry King in 2001. "And I think, between him, the fumes and walking around, maybe picking up pieces or something, he got what is rarely a thing to deal with, but it's Kawasaki syndrome."
"Jett's whole immune system shut down and he got really sick with high fevers -- 104 and 105. He developed a rash on his body and swollen lymph glands -- it was horrible," Preston told the U.K Mirror in 2004.
"Clearly, if anything about Jett's death could reflect badly on Scientology, the organization will go to great lengths to handle the problem," Kent said.
Scientology, the religion that Travolta has followed for about two decades, believes psychiatric drugs and counseling cause damage.
In a 1999 news conference about his movie "The General's Daughter," Travolta disputed assertions that TV and films encourage kids to commit violent crimes and instead linked their cause to drugs.
"My personal thinking is that some of these murders have to do with drugs -- psychiatric drugs, street drugs," he said. "They've found a lot of common denominators are things like Prozac that are altering people's states of mind."
Preston, Travolta's wife, also came to Cruise's defense in 2005, when he was criticized for his public attack on Brooke Shields for using psychotropic medication to ease her postpartum depression.
In a statement to ABC News, the Church of Scientology responded to critics who claim it does not promote medical treatment.
"Scientologists seek conventional medical treatment for medical conditions," the church said in a statement. "Scientologists use prescription drugs when physically ill and also rely on the advice and treatment of medical doctors. The Church does not involve itself in the diagnosis or classification of any medical condition."
ABC News' Dan Childs, Radha Chitale, Eileen Murphy, Lauren Cox and Kirk Fernandes contributed to this report.