But this didn’t stop him forming a unique bond with Jaxon, who regularly came home and told his parents about his daily adventures with Ralph.
Mr Krzysik said: “They were like two peas in a pod together.
“Ralph was all he talked about when he came home some days.
“It was a unique friendship because Ralph couldn’t speak. They had a connection on a different level.”
So far, Jaxon has raised more than £800 for Cerebra, a charity for brain injured children.
The remarkable three-year-old has been going on walks and climbing mountains with his dad since he could walk, and Mr Krzysik said he had hoped to complete the Three Peaks Challenge with his son before his fourth birthday in August.
Now they’ve climbed each mountain separately, Mr Krzysik and Jaxon are aiming to complete the challenge in one go.
“He’s done well, I’m proud of him,” Mr Krzysik said. “He’s always asking, ‘Dad when can we go up the mountains?’”