If chatgpt is bad at something "for you", it means your prompting is bad, which means your thought process isn't fleshed out enough.
Reference the underlying psychological problems (but don't mention diagnoses!). Describe one character as being a Narcissist and the other as being Histrionic and drama will ensue, i.e.:
"Write a story making heavy use of dialogue about a family where the dad is a Narcissist, the mom is histrionic, and the child witnesses a conflict between them."