FOR THE RECORD: An earlier version incorrectly stated that a victim in the Aegean accident used medical marijuana for a war injury.
The relative argued that that some readers may have wrongly assumed that Stewart abused marijuana or took it during the race.
That was never the case, as Stewart avoided the drug before races, the relative said.
Stewart, who won a Purple Heart for his wartime injuries, had a prescription for medical marijuana, the family member said, and only used it to treat a condition.
In addition, the relative said, there's no indication that the minor amounts of the drug played any role in the maritime accident. The relative said the family has been speaking with investigators.
The Aegean was found destroyed near North Coronado Island, about 15 miles south of San Diego Bay. One theory about the 37-foot sailboat's demise is that it crashed or was pushed by waves into the small and rocky Mexican-controlled island.
The U.S. Coast Guard, however, is still investigating the incident and has not released an official cause.
A representative from the Military Order of the Purple Heart said there was no master list of Purple Heart recipients and was not able to confirm whether Stewart received the medal.
The Aegean's skipper, Theo Mavromatis, 49, of Redondo Beach — who was Stewart's brother-in-law — never allowed alcohol or drugs aboard his boat, the family member said.
Stewart tested positive for cannabinoids in a gas chromatography-mass spectrometry test, which is very specific, but the level in his system likely would not have left him under the influence during the race, according to toxicologist Dr. Terence Sean McGee, who is on a panel of Los Angeles County Superior Court advisors.
"All this shows is that this guy had used marijuana, but there isn't enough evidence … to put him under the influence," he said.
The low amount of marijuana suggests that he may have ingested some in the past, McGee said.
Coast Guard investigators have received the information from the San Diego County medical examiner's office, which issued the toxicology report, but could not comment on whether or not it would affect their investigation because it remains open, according to Petty Officer Henry Dunphy.
The Coast Guard plans on releasing a report with its findings on the wreck in October.
lauren.williams@latimes.com
Twitter: @lawilliams30