Gosh I've done and do this. Never thought of it as denial as such, more just outright bloody confusion. Although yes, I guess it is denial. I shy away from denial because it always sounds like something deliberate and calculated, when often it's subconscious, a defense mechanism whatever.

I can only tell you what helps me when I swing between these two states. Firstly, my therapist has said it's not at all uncommon for trauma survivors to do this - swing between different states.

Her response to my swinging, twisting, turning about face is always consistent. That is she always empathetic but she doesn't necessarily agree with what I'm saying. She has no particular opinion about it. In other words I may be swapping & changing my story but she never is.

Instead she tends to reflect back "I hear your saying you think x might have happened" or "I hear your saying now that you don't feel it was that bad" (she is not saying it wasn't bad, just that I don't feel it was that bad). So it makes me feel heard, like she is listening to me.

Occasionally she will push or challenge further, but this is something designed for therapy I don't imagine you'd want to do that in your own home. But you might want to say 'this is something you should discuss in therapy it could be helpful or significant' (assuming there is a therapist).

Also it helps me to be reassured that it's okay to be confused. My therapist reassures me that 'right now you think it did happen' or 'right now you believe you have the story wrong'. She reassures it's okay to change my mind as often as I want, take my time. She also encourages reality checking, evidence collecting and writing it down - keeping a journal. That way you can see your own contradictions or hold them against independant evidence i.e. Jack was a witness to the hold up he saw it happen.

Hope that helps! Must be frustrating witnessing it but I can tell you it's extremely frustrating living it! Very very confusing, and I often wonder if I'm going mad or have some undiagnosed mental illness.