10/28/2014 04:27 EDT | Updated 12/28/2014 05:59 EST

Nathan O'Brien's Parents Speak About Loss And Leaving A Legacy

For the first time since their five-year-old son and his grandparents were presumed killed, Rod and Jennifer O'Brien are speaking out about how they've had to reimagine their family.

"We've been treading water in a tsunami, we're now just crawling back on that beach and looking behind us and figuring out, OK, well, we have to figure things out here and put this family back together or continue on in a new family," said Rod O'Brien.

Nathan O'Brien and his grandparents Alvin and Kathy Liknes disappeared in late June.

For weeks, police and the public searched for the three, but on July 15, police announced they'd laid three murder charges against Douglas Garland.

"We were in a fog," said Rod O'Brien, "It's a parent's worst nightmare, and we still had hope then, but as events have developed over the summer and through July we just had to accept the reality that they weren't going to come home."

New purpose

The parents said they were initially paralyzed by grief, unable to imagine life without their son. Today though, they find new purpose with the announcement of the Nathan O'Brien Children's Foundation.

It's a private charity that's been endowed with a one-million dollar gift from an anonymous donor in the United States.

The foundation will begin granting money immediately to children's charities in the Calgary area.

Rod and Jennifer O'Brien see it as an opportunity to keep their son's legacy alive. 

Story continues after the slideshow:

Photo gallery Nathan O'Brien, Grandparents Missing See Gallery

"We actually get to do an exchange from grief to hope from here on in for ever and ever," said Rod O'Brien. "We get to work with Nathan's spirit and Nathan's name to help the less fortunate as a family."

"It's given us purpose again, helped us get up in the morning," said Jennifer. "It's been huge for us."

Besides new purpose through the foundation, Rod and Jennifer O'Brien said the countrywide outpouring of support helped get them through the darkest days.

"We would love to give them hugs and just tell them thank you to each and everyone out there because they were searching for our family during the most difficult time," said Rod.

We're going to be OK," he said. "We're just moving forward with a new family."

Loss of parents and grandparents

While the couple have both had to learn to live without their son, Jennifer O'Brien is also grieving the loss of her parents.

"My mom was my best friend, so when you look at who you want around you in times like this and who you want to stand by you, it would no doubt be her."

Jennifer O'Brien said she believes her parents would have done everything in their power to protect Nathan and she takes comfort that they're all together now.