BOZEMAN, Mont. -- "His attitude for everything is just amazing and he definitely brought so much happiness with us, and it's going to be hard" said Silver Brelsford.

Silver is just 15, but she knows too well about loss.

Her stepfather Dave Gaillard died in an avalanche while skiing with her mother New Year's Eve.

Silver and her 11-year old step-sister Margo Gaillard remember all the things that made Dave special. He was a respected conservationist, and active in the local schools.

But it wasn't just Dave they've been grieving for.

Their family dog Oly, a Welsh Corgi, was also lost in the avalanche.

"I was going to do a poster of him with a whole bunch of pictures and some cute sayings" said Margo, about plans to have a special remembrance for Oly during Dave's memorial.

But on Wednesday, they received incredible news.

"I was just like, What?! What?! What happened?! She's like 'Oly survived!!!'" said Margo, about a phone call that gave the family the glimmer of hope they needed in the face of their tragedy.

Oly was alive. Rescuers say he dug himself out of the snow, and trekked four miles over four days back to the same motel room David and his wife Kerry stayed in.

He was exhausted but in good shape.

Bill Whittle was on the search and rescue team that raced to the avalanche that killed Dave. He volunteered to bring Oly home.

The family said they are grateful for his kindness because it made all the difference.

"It was a really nice moment because we all had a moment of happiness and it was nice to share that" said Silver, of re-uniting with Oly.

But ultimately, finding Oly can't replace what they've lost.

Margo holds on dearly to those special moments she shared with her dad.

"One of my favorite memories of him is going to the Billings zoo- Zoo Montana- and seeing my favorite animal the wolverine for the first time in my life" Margo said.

But they're happy Oly's home to stay.

"Everything has been really hard" Silver said, adding "but having Oly back, it's brought a little bit more light."

The girls said Oly is still recovering after his exhausting journey, but he is getting his energy back.

"David's family appreciates the tremendous outpouring of support from the community in the wake of the tragedy that claimed the life of David Gaillard," reads a statement released by Tom Gaillard and the Gaillard family. "We share the surprise and delight of his dog Oly’s unexpected return. The invincible spirit of the Welsh Corgi who was able to dig himself out and return after four days in the wilderness is an inspiration and a joy to all of us."

"We are focused right now on celebrating David’s life. He was a wonderful young man who made an immense contribution to the community and to regional conservation efforts. He passed away far too soon and we are deeply saddened."

The family is holding a memorial service for David tomorrow at the Springhill Pavilion north of Bozeman at 2 pm.

And the family says in lieu of receiving flowers, they've set up a memorial fund for programs close to David's heart. To donate, you can visit the memorial fund webpage by clicking here.