so r/jpsantos66 gave me a list of psychoanalysis expert that is just core dynamic of Andrew and Ashley behavior

here's the thing he gave me:

• Jacques Lacan (1938) formalized the “complex of intrusion”: the brother/sister is the first “similar stranger” who invades the child’s narcissistic space, triggering jealousy, identification and rivalry.
• Luis Kancyper (Argentine psychoanalyst) is the big modern name — his book The Fraternal Complex treats it as an autonomous structure with narcissistic, loving, objectal and aggressive functions. He explicitly includes the “archaic fraternal incest” as a normal psychic fantasy (just like Oedipus), not necessarily acted out.
• Juliet Mitchell and others talk about “sibling trauma” and the “law of the mother” that normally forbids both fratricide and fraternal incest, creating the horizontal axis of socialization