Answer: According to Freud, Shelia may be using the defense mechanism of projection.
Explanation:
The projection mechanism is when a person takes the attributes in themselves that they dislike/hate and projects it onto another person. This can cause hurtful things being said to someone, in this case the sister. By using the features someone dislikes on themselves they use false accusations towards others.
When someone is using the projection mechanism they are repressing their own feelings. They are unable to handle their own flaws. Some of the things that can be projected to others are;
