Thanks a lot, Wendi. The problem is that his company switched from regular Medicare to Advantage about 3 years ago, so some of his doctors that he's been seeing all along no longer accept his insurance. He's getting forgetful and a bit confused, and if he goes to appointments alone, he doesn't remember to tell them about having Advantage instead of regular Medicare. We especially have trouble with labs, who always submit to regular Medicare even though they have the correct insurance information from his doctors.
I didn't know we could get a list of approved doctors from medicare.gov, I will definitely check that out.