Mom Dying of Appendix Cancer

Wondering if anyone has any experience to share about someone dying of appendix cancer? My mom was dx in December 2014 when her "appendectomy" revealed a ruptured tumor growing from her appendix; it was later determined to be mucinous adenocarcinoma.  I think it is important to note: the local hospital pulled the tumor through a small, robotic incision, no doubt spilling the mucus in her abdominal cavity and exacerbating the problem. 

After months of chemotherapy, we sought a specialist for HIPEC surgery, landing us with Dr. Alexander at UMMC. (No one in Philadelphia would touch her - we learned to seek the specialiist and not the hospital.) Although the results of the surgery were deemed successful, the cancer grew back quickly and here we are 2 years later, out of options and my mom is actively dying. 

She has declined quickly in the last few months. By August, she was unable to walk long distances and needed to rest every few hundred feet. In September, she began to really feel the effects of the growing cancer: finding it increasingly difficult to leave the house. Now in October, my mom can barely eat or drink, let alone stand. She has ragged breathing, uncontrollable, jerky movements and is exhibiting all the typical signs of death according to the internet. 

I've struggled to find information on the internet about death from this particular disease. My mom's tumors have broken through her skin in her abdomen and are growing outside of her body now. They seep and weep and smell awful. She was in a great deal of pain until her Oxycontin and Morphine was steadily increased; now she is in some alternate reality and not lucid, but not in pain. She has hallucinations and delusions; she thinks we are "out to get her" and "trying to kill her". She has thrown herself on the floor declaring that she is trying to commit suicide and told me in the bathroom that she "heard everyting and knows our plans."  I'm reeling over not only the loss of my mother physically, but also emotionally. She has stopped connecting, caring, emoting, and being the mom I knew in those ways. She is speculative, suspicious, and borderline mean. I know she is dying, but I'm struggling to handle this treatment from her while I help her.  She yells at me to "hurry up" in the bathroom because she "needs to get back to bed." When I cry, she tells me to stop. No emotion, no reasoning: just stop. I try to stop, but the woman I am caring for, full-time, with time off from work and my family, is my mother. My invincible, strong mother, who apparently no longer has the ability to meaningfully interact and is aggravated by my every move.

Since there seems to be limited information on all of this available on the internet or anywhere else: my questions are these: (1) Has anyone else experienced theese things? if so, how have you handled it? I need help... (2) How long can this delusional state continue? She has no quality of life and is deteriorating; when will this end? (3) How do I cope with dealing with a mother that is cold and cruel - the opposite of the mother I knew growing up. I am struggling to be okay with her berating me and implicating that I am out to get her in some way.  

I feel lost... and sad... and alone... has anyone dealt with any of this????

Thanks for your time. I don't know what else to do...

jen