Do you mean can he bill for seeing patients who have a Medicare Managed Care Plan? Not patients with straight Medicare? Participation in the Medicare Managed Care Plans are separate from the straight Medicare. If he has an application in to become a Medicare provider, that does not automatically enroll him in the Managed Care Plans.
You need to contact each of the Managed Care Plans that he wants to see patients in and see if he is in network. American Progressive Today's Options does not require any paperwork for a Dr to be in network. Just accepting the patients and submitting the claims for payment constitutes as in network. If he is a BCBS provider, he is probably already in the BCBS Medicare Managed Care Plan, but you need to check.
Each plan has different guidelines.
Michele