I saw where towards the end of the last thread, there was much discussion of AJ being adopted and changing her name. Here is my take on that....
AJ had always used ZH last name. He had raised her since she was 1 1/2 years old until she was about 13. So Mom, AJ, ZH, and the children born of Mom and ZH all had the same last name. WH comes along and marries Mom (not long after they meet). He can't change the siblings names, because ZH is in the picture, but he can drive a wedge between ZH and AJ and manipulate the situation so that AJ's name is changed. The name change was not about AJ, but about WH "winning" over ZH. WH is a master manipulator. I would definitely speculate that there is an underlying mental health diagnosis in there somewhere. JMO, MOO and all that good stuff.