Matt Stapleton and his children (from left) Ainsley, McEwen and Issy
By Jeff Truesdell
07/01/2014 at 01:00 PM EDT
As his wife heads to trial for the attempted murder of their daughter with autism, Matt Stapleton is steeling himself for a verdict and what might follow.
"It should be black and white – it should be easy to deal with," he says in an exclusive interview with PEOPLE. "The reality is, it's not."
Prior to his scheduled appearance Tuesday in a pretrial hearing, Matt broke his long silence to describe the "amazing" rebound and challenges still faced by his 15-year-old daughter Isabelle – nicknamed Issy – since the Sept. 3, 2013, failed murder-suicide attempt by his wife, Kelli, whose trial begins July 16.
Kelli, 46, has pleaded not guilty, and faces a maximum life sentence.
After she and her daughter were found unconscious from carbon monoxide poisoning when Kelli allegedly lit two charcoal grills in a closed van, Kelli – a high-profile blogger on autism and, with Matt, a determined advocate for her daughter's care – said that after years of Isabelle's physical abuse targeting Kelli and other family members, she "thought this would be the best solution … if Issy and her went to heaven," according to police quoting from court documents.
Says Matt, 42, a high school principal who lives in Elberta, Michigan: "Who knows when and if she made a decision to do what she did? At whatever point, she felt like that was her only option. And I think there are other parents that fall in that category."