Brenda Brenda:
This is not a Pyrenee. It's a Kuvasz.
According to the Vet, he was "mentally ill".
My bad, initially it looked like a Pyrennes. But after looking up the Kuvasz in my handy dog breeds book I'll leave you with the line they use to describe them.
"A prospective owner requires considerable experience of handling difficult dogs before introducing the Kuvasz into normal household circumstances."
I honestly don't know how experienced your parents were with dogs but this would be a breed I would avoid if I had young children.