AIO for blocking my best friend after she wanted me to pay for her car payment?

My brother asked me for help with rent. I told my best friend about it. Next day she asked me to pay for her car payment.

For context: I have a 25 year old brother with autism, I sometimes financially help him and my 25 year old sister. All of us are not emotionally close, but our mother died and our dad ran off with the life insurance money to spend it on his new wife he married after six months of knowing her, walking back all the promises of financial help he gave to us kids. I pick up the slack by supporting my brother and sister through tough times financially. My mom’s dying wish to my father was to take care of us kids, so I try to honour her wish.

This year I also gifted my sister and best friend a vacation, and this summer I covered for her an unexpected expense of $900 for best friend, and she hasn’t paid me back yet like she promised. I was waiting for her situation to improve before setting up a payment plan with her.

My friend in the screenshots was like sister to me. She can no longer afford her car insurance because she got into 3 accidents and had a speeding charge. She works full time and lives at home with her parents rent free, but it’s very chaotic at home.