how did billie, chris's mom, treat her own son?

There isn't too much about Chris's mom after the beginning of the story.She is a very petite woman who meets Walt while working as a secretary at the company he works for before they split off to start their own company together. Like Walt and her children, she is very passionate, with a strong temper.She of course loved Chris, but I think she had no inkling that Chris would take off into seeming oblivion.