No magic wands here... I will send a hug and lots of good thoughts and wishes in your direction, and a few prayers can't hurt either.
Don't take too much on yourself. Your siblings should be there for each other, you don't have to be strong one, or do it all yourself. No one would expect you to do that, all you can do is the best you can, and be there when you can.
As for support, I'm sure the hospital can recommend some places for you, and I'm not sure where you are located, but one outstanding organization, you might want to look at, for both your mom, and for your family, is
Gilda's Club, I honestly can't say enough good things about them, I've volunteered my time and money to them for a few years now, and they will be there when you need them.
Just remember you aren't alone, good luck.