Chemo didn’t work as they hoped

I'm devastated. My dads chemo didn't work as they had hoped. 6 months of seeing him suffer through the side effects of chemo down the drain. When they did the midway ct scan and at the end, they reported shrinkage but after surgery they said it wasn't as they hoped. im not sure what I want by posting this, I'm sad, mad, frustrated and scared of losing him. I don't feel like answering his whole history but it just sucks. To know that it didn't work and although they took it out, it could have spread. How do you deal with the feeling of dread and being scared that maybe your child won't have memories of your dad. Looking for some prayers, positive vibes and maybe positive stories. Honestly at this point I don't need someone telling me the brutal truths about it, I'm already heartbroken.