While it's really disrespectful towards those guys and their families to sue and I totally don't agree with her suing the family, imagine this.
You're driving down a road, paying attention to the road when you suddenly hit a person you couldn't even see coming. Those guys had no lights on them or anything, so in a way it is their own fault. You have killed one person and heavily injured another one without having any intention to. You want to comfort the family but they do not want anything to do with you.
And like always with these kind of incidents, rumors spread that you were drunk driving or something else that you shouldn't have been doing behind the wheel, which isn't true at all. Basically, your entire life just falls to stuff and to top it off, you're being sued for everything you have.
Like, if I was in this situation, I wouldn't sue or do anything that could harm the family, but I can sort of understand where this lady is coming from.