Sister with triple bypass with 2 not working

[BF0506]

My sister went in Jan to have a triple bypass actually she was to haensure a quad. The Doctor only did 3 and said her veins were to small to do the 4th one. She went back in on Aug. 18th and with a mild heart attack, they went in and did an angioplasty and when she came out they told her that she had a block in the one and only one working 2 of the 3 are dead. They also told her that it was calcified and if they tried to remove it or blast it that it would break off and go to her brain. She has very small vessels and they told her that there was nothing more they can do for her so they have had her in giving her Coumadin and will be sending her home with the  blood thinners. Is there actually nothing that can be done? She is only 57 and to me it sounds like they are sending her home with a death warrant? Can I get some help or advise on this because I have heard a cardiologist tell my brother that there is always something that can be done? She lives out of state so I cannot keep an eye out for her. My heart is just breaking for her!!!!!!!