From left: Tyler Clementi's brothers James and Brian, his mother Jane and father Joe, photographed in Nov. 2011
Nearly 15 months after Rutgers University student Tyler Clementi killed himself
by jumping off the George Washington Bridge, "not a minute goes by that I don’t think about him," his mother, Jane
, tells PEOPLE in an exclusive new interview.
"It's especially hard right now because this was his favorite time of year," says Jane, 53, a nurse, of Ridgewood, N.J. "So we're trying to find a new way to celebrate Christmas. I'm sad – and trying to get through it."
His father Joe says when he's thinking of his son, he'll look at a Facebook page in Tyler's honor.
"I'll read a few things until I get choked up – then I'll stop," says Joe, 55, public works director for the borough of Hawthorne, N.J.
Tyler, 18, committed suicide three days after his roommate, Dharun Ravi, allegedly used his webcam to watch him kissing another man and streamed it live on his Internet chat group. Ravi, 19, was charged with 15 offenses
, including bias intimidation, a hate crime but not with causing Clementi's suicide.
He has pled not guilty to all charges, and goes on trial Feb. 21.
, 19, whose laptop Ravi allegedly used to watch the encounter, has agreed to testify against him in exchange for admission into a first-time offenders program.
For their part, the Clementis hope to help prevent similar tragedies with the foundation
they created, which will fund programs for gay teens, bullying and suicide prevention.
"It wouldn't be fair to Tyler's memory
to let this slide," Jane tells PEOPLE. "Something good has to come out of this terrible situation."
For more from the Clementis, pick up this week's issue of PEOPLE, on newsstands Friday