Don't let the worry get to you, that's what Satan wants, because when you worry, you are doing nothing but saying "God, I don't trust You to let this work out for the best." Satan would like nothing better than to do that. Just put all faith in Him and let the worry leave, because regardless of what it may seem at the time, the end result when left to God is the best possible result that could take place. Also, if something doesn't turn out the way you want, remember that He knows better than you, and it may seem bad to you the way something turned out, but in reality, He knows it was better for you in one way or another. Never turn against God because things didn't go our way. A 4 year old would reach for rat poison, thinking it's candy and wanting to eat it, while his father would reach and stop the child, telling him it's not good for him. However, the child would resist and yell, not understanding that it's bad for him, since it seems to be candy. This is how we work, we're children compared to Him, and He, as our Father, knows better, He knows what is good, and what is bad for us, despite what we think is good or bad, since we're like that naive child that would eat poison unknowingly, mistaking it for something good.
My Dad died of cancer on the 31st, just a little while ago, and I got through it without the least bit of a problem, because I know God is taking care of Him, and that He is comforting me. My aunt then stole everything of his from me by getting him to make a will while his mind was gone (the man was trying to drink cell phones, that's how far gone), and took all the sentimental objects from me, as well as lied to the family about my Mom and I, yet I feel no worry, no anxiety, no anger, nothing, because it's all in His hands, and this life is temporary, so why get upset over the loss of a temporary thing? And why be upset over the fact that my father is far better off, no longer sick, and with all his old friends, as well as his parents?
This life is like a prison, when one of our friends in that prison gets parole and goes free, we should be happy, not upset and want them back in captivity with us. God is seeing if your mom can get parole, that's all. If not, you get to hang out with your friends in prison longer, and if so, one goes free. Either way, things work out fine, remember that. Death is not the end, but simply the beginning of the way life was supposed to be.