My Mom's Medicare card was stolen from her room at her memory care facility. What do I do now?

My 94 yr old mom is well into later stages of dementia, I am POA, and I have done a good job for years of caring for and protecting her. I didn't realize her Soc Sec # is on her Medicare card. Her ID may have been stolen. How could I miss this! I took a copy of this card for my purse and thought she should keep the original, and her photo ID. That card is old, it looks like a drivers license but she's never driven. I stopped leaving any money in her wallet (altho she nags constantly she needs money "just in case") because at the beginning small amts of cash were disappearing. If a thief has her soc sec number and photo ID, can her accounts be compromised? What steps should I take? There was nothing in her purse other than those two pieces of ID.