While something like this should never happen to anyone, it's Barbs own doing and I'm positive Barb was consensual. But, being decent human beings (the court) I'm pretty sure they don't want to drag her down more than she already is. I mean she's a terrible person, but:
she's also old af, no real family, no real income, who's now outed to having sexual relations with her retarded son who's also the village idiot, and is already despised in the community (both her and Chris) Lawyers may not have souls. But they do have standards, unless you know. Scorched earth, balls deep bring her to the stand, etc.