I stumbled upon this great article about Medicare and Powers of Attorney and how it can help you make Medicare decisions.
Basically, Medicare will not share your information with anyone including your spouse. And just having someone authorized as your Power of Attorney will not allow that person to make Medicare decisions on your behalf. Medicare will require written consent from you to authorize someone to act on your behalf.
There are a couple of forms you can fill out and send to Medicare. For more information about this important issue, please head to this article post “Medicare and Powers of Attorney“.