Can You Give Me Some Advice About My Crack Addicted Sister?

My sister has been hooked on crack for 10 years. I am raising her son. She is 30 and has never had a job or been responsible for anything in her life. When my mom died a few years ago, her will said that whatever money my sister received from her life insurance should be held in my trust. That money has run out and now my sister is receiving settlement money from the lawsuit over my mom’s death. (mesothelioma) This money legally doesn’t have to be held in my trust. It could go straight to my sister but she agreed that because of her drug issue, my brother and I could hold on to it for her so she doesn’t go blow it. There is about 75 thousand dollars total. Well, a year has passed and my brother and I are fed up being responsible for this money. She is constantly calling asking for more money, even though we agreed on a set budget. Obviously she is going and blowing this money on crack. We don’t usually tell her no because legally, it is her money to do with what she wants. But we are so sick of the lies and deceit and the constant calls. And we are scared that drug dealers will show up at our house because she has told them we have all this money for her but won’t give it to her.
If this were your sibling, or your adult child, would you just give them the whole 75 thousand and let them go blow it on crack?. Even though you know there is a good likelihood it would cause her to overdose and die? Or would you just keep answering the phone calls and give it to her a little bit at a time so she will be less likely to be able to go on a massive binge that will kill her?
My brother and I are so sick of all of this but at the same time, we don’t want to live with the guilt of knowing that she died because we gave her all that money at once.
And she absolutely refuses long term rehab. She went a couple of times to 30 day programs, but she left to smoke crack within a week of getting out.
Is there anyway to get legal control of her money because of her addiction?
Thanks for your help.