What would be a good thesis statement based on the character of the grandmother?

The grandmother is the central character in this story by Flannery O'Connor. The transformational experience of the grandmother finds her being judged by a murderer who has cornered her family.  

He, Misfit, finds the grandmother lacking he criticizes her the same way that she tears into her son and his family always complaining, finding everyone beneath her, feeling superior to everyone.  It is a deliverance of justice in a creepy, eerie way, that grandmother would be sent from this world from someone that she would ordinarily not give the time of day to, had she not been held hostage with a gun in her face. 

Misfit, the killer, brings out the best of grandmother, changing her, reforming her, bring her to her knees, finding her compassion for another human being, except its too late.

She is a selfish, demanding, controlling individual whose forced decisions on her son and his family actually end up getting them all killed.  The grandmother is so self-involved that she can't even see that her selfishness has led to tragic disaster for the family.

"If the Grandmother had not insisted they detour to see the old house, which, she realized too late was in Tennessee, not in the part of Georgia where they were, the family would have escaped the disaster." 

Grandmother has set in motion the fatal events that take place, her poor family is sacrificed at the hands of the murderous thugs led by Misfit.  

She tries to talk her way out of the confrontation with the evil men, but to no avail.

"Listen," the grandmother almost screamed, "I know you're a good man. You don't look a bit like you have common blood. I know you must come from nice people!" (O'Connor)

Grandmother makes Misfit so uncomfortable, he recoils against the thought of her calling him one of her own babies, she brings out the worst in the murderer, who seems to enjoy shooting her three times just to shut her up.

"His voice seemed about to crack and the grandmother's head cleared for an instant. She saw the man's face twisted close to her own as if he were going to cry and she murmured, "Why you're one of my babies. You're one of my own children !" She reached out and touched him on the shoulder. The Misfit sprang back as if a snake had bitten him and shot her three times through the chest." 

"She would of been a good woman," The Misfit said, "if it had been somebody there to shoot her every minute of her life." (O'Connor)