Any negative comment should be addressed in writing and documented on a DA FORM 4856 and/or the DA FORM 2166-9-1.
They cannot falsify the counseling dates. Your senior rater was right to remove the dates and insert a comment into the senior rater portion of the NCOER. If his comment is not factual that is another issue.
If you have a copy of the NCOER with the false counseling dates and the Senior rater does not have any documentation for the negative counseling you can use this in your appeals process or commander’s inquiry.
AR 623-3 and DA PAM 623-3 cover the requirements to document the counseling sessions.