Diane Schuler's brother and father of the three girls killed in the wreck, Warren Hance, is reportedly not speaking with Daniel Schuler.
"We would never knowingly allow our daughters to travel with someone who might jeopardize their safety," Hance family spokesman Stephen Spagnulo said on behalf of the family.
Experts don't agree with Barbara's proposition that a medical condition was the cause of the wreck.
"If they found elevated alcohol levels in her blood, she must have ingested it," said Fayad. "Unfortunately, alcoholism and drug addiction are often missed or underestimated by family members."
Alcoholism, which affects 9.6 million people in the United States, disproportionately affects men more than women -- 6.9 million men compared with 2.5 million women, according to the National Institute on Alcohol Abuse and Alcoholism -- but women are uniquely susceptible to the effects of alcohol.
With less water in their bodies, women take longer than men to break down the toxic compounds in alcohol, with the result that the same amount of alcohol exposes a woman to more alcohol for longer periods of time than for a man.
And the associated shame and stigma of the disease makes it less likely that an alcoholic would seek help from family members or seek professional treatment.
Still, Daniel Schuler insisted during the news conference that he had never seen his wife drunk and that "she was the perfect wife."
"We had an occasional pina colada at a family barbecue," Jay Schuler, the wife of Daniel Schuler's brother, said on "GMA" last week. "She was meticulous, safe, I trusted her with my son when I left the country ... those three girls before her own children were her life."
"This is absolutely not the woman they know," she said. "[Not] who I trusted my children with."
Barbara reiterated that "the family believes she did not ingest," but if that belief proves false, they want to know "what may have caused her to ingest if she did."
Last week, Barbara suggested that Schuler may have ingested alcohol in an attempt to raise a low blood sugar level, a theory experts said demonstrates a fundamental misunderstanding of both diabetes and stroke.
"Blaming the accident on a stroke preceding it is possible, like anything else, but not plausible," Fayad said. "Having high or low blood sugar acutely does not cause a stroke. It is the long term effect of diabetes that increases the risk of stroke."
Low blood sugar can mimic stroke. The brain is reliant on a consistent supply of sugar and oxygen from the blood, without which it may begin to lose function.
But a diabetic person's blood sugar level is higher than normal because it is not well regulated by insulin. Left untreated, as Diane Schuler's type 2 diabetes condition was, blood sugar will remain high.
Without proper medical controls, a diabetic person's blood sugar can increase enough to put the body in a crisis situation. Extra sugar seeps into the urine, drawing water along with it. The body becomes dehydrated and blood potassium levels climb, causing the brain and other vital organs to suffer.
Similarly, alcohol is a diuretic that draws water out of the body, causing dehydration, and can compound the effects of elevated blood sugar.