Hello and thanks for using Just Answer.
My name is Al and am happy to assist you with your enquiry.
So that i can answer you fully, are you sure your Mother mentioned you and your sister had rights to act if she lost mental capacity in her Will? (It would normally be stipulated in a Power of Attorney document, and not a Willl, as a Will only comes into action upon someone's death).
Could you please also just clarify what other question you need answering?
I look forward to hearing from you.