She is the legal executer of the estate. Legally, her name has to be on the suit.
The wife of the nutjob is just as big a victim as the widow of the innocent bystander, who should she sue? She has no recourse except to collect what insurance she can, if indeed she has insurance. She no longer even has a house to live it if the reports are correct.
IMO, this law suit is not justified and is a despicable act.
She's not being sued as the executor of the estate, she's being sued for negligence, or so the media reports claim. You're making it up, now.