Mom Has Stage 4 Cancer, Living Off Ss, Received Notice Of Levy

As the title states, my mom who is battling stage four colon cancer, is unemployed because of that, and living off of Social Security received a notice of levy in the mail today.

She has received no prior notices, does not recognize the creditor, or the amount. We think it may be fraudulent and never came out until now.

All that to say, I am looking for advice as to how I should best complete the exemption form. She receives less than $1,000 in social security and receives a monthly donation from her church. Does this need to be hand-delivered to the sheriff or can it be returned certified mail? How can we dive deeper into where this is coming from? Is there anything I need to do to protect myself or other family members from being roped into this? She and my dad are separated and we are in the state of California.