Absolutely.
Sonja appears to be a crazy person.
She is insensitive, self centered, volatile, and manipulative.
She thrives on causing drama and turmoil in family.
She twists everything around to be a personal insult and accepts no blame for anything she has done.
It is likely Sonja person has a narcissistic personality disorder.
These people create absolute chaos in their families. But Doctor Phil has a blind spot in recognizing these people for what they are. The closest he comes to recognizing them is to call them “right fighters” And then misplaces blame to others in the family by stating “you deserve each other.” The chaos created by these people is 100% the fault of the person with NPD. Families will say things in response because they don’t understand what they are dealing with and still want to believe they are dealing with a normal person. For the most part, any improper actions or statements by other family members are a reaction to a difficult situation. But they did not cause this situation.
Using the will as a weapon - This is a tactic I am quite familiar with from a family member with this personality. This attempt to control people with money is a symptom of the BPD.
I doubt that Dr Phil can fix this situation with family counseling.
Allowing Sonja to eavesdrop on the conversation between the sisters was wrong. It was a betrayal of trust to the daughter. Under normal conditions, it would be illegal. For a person with NPD (Sonja) it will produce no understanding and only provide more issues and statements to use against the out-of-favor family member.