The Lost Boys actor passed away of natural causes one year ago today, at the age of 38.
Judy told Entertainment Tonight Canada that she sometimes pretends that her son is just working away when she thinks about his absence.
"It's harder for me because, as you know, I lived with Corey… and we've spent so much time together, and we've done so much stuff together, and we went on holidays together," she explained.
"It's, like, mindboggling ... I do pretend sometimes that he's on location somewhere."
Judy continued: "I have his pictures all over the walls.
"I have my good days. And… all of a sudden I'm getting this wave that's, like, impossible to deal with."