Brother's myeloma treatment no longer working. So scared

My brother was diagnosed with Multiple Myeloma last March so in 2021. He is 62. He has been through chemo, radiotherapy and very high dosage of steroids. He was then put onto numerous drugs of a thalidomide nature. The drugs have stopped working so they have withdrawn them. I am so besides myself upset as I am potentially going to lose my oldest brother soon and it scares the *** out of me. Every member of my family has been affected by cancer and I'm the only one that hasn't.