Here is a new one for me:

We have a sex offender going to counseling. Dr. has been told by private attorney that he cannot talk to offenders probation officer about his meetings/sessions with sex offender.

1. True?
2. What can I do, short of strangulation, about it?

You might try modifying the terms of probation to include that the defendant execute a release authorizing the good doctor to release all records and to discuss the patient and his case with his probation officer or his/her designee.

Be sure to include the right to discuss the patient/case with the holder of the release. Otherwise, you may get a few meaningless pages of notes and nothing more. The "discussion" will get your questions answered.

Strangulation is quicker.

Is the lawyer representing the defendant, or is he advising the doctor? That isn't clear from your query.

Here are my thoughts off the top of my head:

There is no physician/patient privilege in criminal proceedings (outside of drug/alcohol abuse treatment). If the private lawyer is parsing that to mean that the shrink can't speak to the PO outside of an actual proceeding, then just ask the defendant to waive any confidentiality -- it is his privilege, not the doctor's. If he won't do that voluntarily, then it could be made a condition of probation, or you could subpoena the doctor to court and force him to talk during a "criminal proceeding" of your choice. But I'd try the easy way before resorting to the hard way.

Defendant already has a condition to meet with his probation officer. Case law interprets that condition rather broadly for the defendant to do more than simply show up in the probation office. He must "report" what has been going on, including any counseling. Failure to do so is a violation of the condition.

Warn the defendant once. Then file a motion to revoke. He can work out the legal niceties while pending the hearing.

This is the sort of legal gamesmanship that gives some lawyers a bad name.