The late 'Glee' star, 31, who voluntarily checked into rehab for the second time in March for a month to battle his drug addiction, checked in to the Fairmont Pacific Rim hotel in Vancouver, Canada, on July 6, and sought support to help him maintain his sobriety shortly before his death on Saturday.
A source close to the actor told gossip website RadarOnline.com: "Cory went to AA meetings when he got to Vancouver with some friends of his and mine. They have attended AA meetings in the past together.
"Vancouver is a great place to keep grounded when you are in the spotlight and trying to be sober.
"Being grounded is the key to sobriety and that's what Vancouver can offer Cory. It is casual and he calls it home and he has friends here who have known him for a long time.
"Cory also works helping kids stay out of these drug problems that are so apparent in the Downtown Eastside."
The insider also insisted that despite being spotted out with friends at the Portside bar in the hours before his death, Cory was not drinking.
Meanwhile, 'Glee' producers are reportedly scrambling to figure out how to move forward following their leading star's sudden death.
The new series was set to start shooting next month and executives have scheduled a number of meetings to discuss story lines without Cory's character, Finn Hudson, according to Foxnews.com.
The Canadian actor's girlfriend and co-star Lea Michele, 26, is said to be "absolutely inconsolable".
A cause of death has yet to be determined.