Civil suits for huge damage claims should be filed by the parents against the judge along with a massive PR campaign to get the public onboard. If the suit is denied because "you can't sue the judge", the public will ask why not and be ripe for change.
I really don't like the idea of being able to sue a judge over a case. Are there huge abuses by some judges? Yes. But being able to sue over any case a judge decided on would ruin the concept of judicial independence in this country. Every judge would end up worrying more about what covers his @$% the most and not what the correct ruling is. You'd be opening some cans of worms you really wouldn't want to open.
To this judge, it was just another file jacket on his desk, most likely. They typically do not take such matters very seriously since liberal appeals court judges appointed over the past 30 years will reverse rulings that actually do justice.
If the families of victims could sue judges and parole board members, even in limited circumstances, these folks would view their jobs quite differently.