What can I do if my sibling is using my mother's credit card?

Mimi, we need more information. What are your Mom's medical needs? Is she living in senior living, or in your home, or in your sibling home, or still on her own? How do you know that the sibling is using Mom's credit card? Is Mom telling you that? Is sibling telling you that?

What is the sibling purchasing? Are they items that Mom needs or personal items for the sibling? Did Mom give the sibling permission to use her credit card? Is sibling paying Mom back for any personal purchases?

Who is the primary caregiver for Mom?  Who is/are her Power of Attorney?

I know it's a lot of questions, but it will give us a better idea what is going on :)

Our Mother is financially self sufficient, doesn't need any financial assistance from us or sibling. Mother has been living for past 18yrs with My sibling in order to help sibling raise 3 boys. They are adults now. Sibling has a history of living beyond her means and has been bailed out financially two previous times by ex-in laws. Four years ago she file bankruptcy to avoid paying her credit card debt. Our mother recently has begun to show need for supervision with preparing breakfast/lunch during the day when sibling is at work. We asked sibling to hire daytime helper at $25 per hr with mothers money and she disclosed that there's no money for that. Mother has a pension, had a savings that had $25k three yrs ago. Don't know if savings is still existent at this point. During this conversation she disclosed the credit card balance being $18k. Mother has been unable to drive, write a check, or cook since her stroke. She is dependent for her care now.

We also asked sibling to produce the credit card statements and refuses to do so. We have not made mother aware of our concern over her credit card and savings since lately she has been showing signs of depression and talking like she won't be around next year so I don't want to bring her this issue. My sibling admits to charges belonging to her and is hoping if mother dies the debt will be forgiven and this pisses me off. Sibling is very difficult to deal with so it's not pretty. I don't think there is power of atty. since the stroke. There was a medical power of atty which I was sole designee.

When our father died 30 yrs ago, this sibling was sole beneficiary of his pension and property not our mother and I see her doing same thing.

This is complex. I would highly recommend you talk with an Elder Law Attorney regarding these issues.

Curious why your Dad, who passed 30 years ago, didn't give his pension and property to your mother so she could continue to live comfortably as she aged. Or were they not together at that time?