I know you are, you said you are, but what am I? Is an old childhood retort to name calling. He seems to be doing a version of that. It fits DARVO very well.

Deny- no, I didn’t do X.
Attack - YOU did X
Reverse victim - you falsely accused him of X!
Offender - that’s now you for accusing him of X.

It’s to put you on the defensive and is a form of gaslighting.