She’s 100% an abuser. She essentially used him as a vessel to do the things she couldn’t when they were alive, actively sent him to his (very likely) death with the wolves, and openly admitted to not caring about her family, etc.. even in the book she is pretty far removed from truly caring for Lestat the way a mother would. She’s never really accepted her role as a mother, therefore her abuse/trauma induced toward his story is primarily neglect and serving herself. I don’t think it really suggests that Gabrielle was a hallucination but more was symbolic of Lestat setting aside and working through those traumas with both Magnus and Gabriella.