PCP treating pt for medical condition while in Psych facility

We have a PCP who visits patients who are in a Psych treatment facility. My Dr is treating the patient for typical PCP stuff, ie hypertnesion, esophageal reflux, hyperlipidemia....He often bills a 99223, which Medicare has been requesting medical records on....What is the fine line between providing medical records to substantiate his claim vs. crossing the line w/ providing documentation to insurance about patient in psych setting? Often times the patient's HPI is psych related, but Dr is seeing them for other things besides psych....I am thinking that my Dr's HPI should only be related to what he is seeing the patient for, am I wrong? Where can I find guidelines related to this?

Thanks

PCP treating pt for medical condition while in Psych facility