Worried daughter in law

Hello everyone, my mother in law has IBC very aggressive stage 4 metastic its in her breast, lymph nodes, liver, bones & brain. She started doing radiation to the brain but after her second treatment of radiation her brain did not react well. Her brain swelled up to a point where her left arm she couldn't move it. She already had her left leg not moving then after her 2nd radiation her left arm was not able to move. They did a scan to check whats going on and the brain had swelled up due to radiation. Now I want to know what do we do because if we continue radiation she can go thru same thing her brain can swell and the doctor told me it can come to a point where she can stop breathing due to that. My mother in law wants to move to palliative care and no longer wants to do chemo or radiation. I don't want her to give up yet, she did only 2 radiation treatment on brain and 6 chemos.........its not enough yet I want her to keep fighting!!! Please any suggestions or advice....thank you all and GOD BLESS! xo