I think it's pretty common to hear the "old tapes" of the dysfunctional members going through our heads, even when we're no contact.
I used to have conversations with various toxic people in my head. I'm not entirely sure when it stopped or why. I suppose I hit a point where I'd let go of all the horrible stuff they said to me and didn't believe it one jot, so didn't feel the need to argue with it anymore.
But the "old tapes" are still there, telling me I'm stupid or worthless or calling me a ***** or whatever it is. When those pop up, I remind myself that "that is not your voice" over and over again. It helps that my husband tells me the same thing when one of those old tapes actually gets spoken aloud (to myself, usually putting myself down). One day I asked him how he knew that it was not my voice, how could he be sure that I didn't think that? He replied that I would never say that to anyone else in the same circumstances (for instance, if someone were to break a glass in my house, I wouldn't think twice about it, I'd just clean it up and move on, graciously accepting their apology - but I would spend the next 24 hours beating myself up over it if I did it).
I thought a lot about my husband's comment. For quite a while, I used to tell myself "Treat yourself the way you would treat others - that is not your voice." And I would force myself (often out loud) to say to myself what I would say to someone else in the same situation. Then I got to where I could instantly identify what was my voice and what was not my voice. Then I started attempting some evictions: "You're not my voice...You! Out!" I still will say "You're not my voice" out loud.
I do still slip into arguing with toxic people in my head. I believe it's a way of trying to resolve things, trying to create a different ending to a bad situation. To limit that, I started keeping a journal where I write letters to the various people I'm "arguing" with. I put it all in there (especially if it's keeping me from sleeping). It often brings me to tears. Something about seeing it on paper... I don't ever plan on sharing my collection of letters with anyone, but it is very cathartic to get it out on paper. And it does seem to end the 'argument'.
But even now, when I've walked pretty far down the path of recovery, I still have arguments in my head with toxic people (not always family members, there are plenty of toxic people to go around in this world). Sometimes I succeed in putting it where the blame lies "Well, this will probably never resolve, the problem lies with them, not me, and I can't change them." Sometimes the recognition of a lack of possible resolution is resolution itself.