raising our granddaughter who has ostresarcoma(NBED HELP ASAP)

We really need some advise, ASAP
We Picked up our granddaughter Sept 2008 before cps got involved. Kayla was 2 at the time. We had lots of emotional times with our daughter at the time. In April 2009 Kayla was diagnosed with Ostresarcoma in her left leg. She went through 34 weeks of chemo, and lost her left leg above the knee. She did really well with her new prothethes and did almost anything she wanted. Rock climbed, snow skiid, riding a bike. Her mom moved out by us in Dec. 2009 and we have been fighting for kayla ever since. It's been really hard on Kayla. She does not want to move back with her mom. In sept 2010 Kayla was diagnosed with the same cancer in her right leg. She is now doing chemo, and they are discussing what to do with the leg. She is 5 yrs old now. Kayla and her mom do not get along. Her mom is havine lots of frustration with why Kayla doesn't except her. I think Kayla is scared of her mom leaving again. Anyway, Her mom (our daughter) is really causing alot of stress in our lives. We are at the breaking point. she yells at us and swears at us. Caused problems at the hospital. you name it she does it. We almost want to give kayla back to show her mom how hard this is to take care of kayla. Kayla needs 24 hr care 7 days a week. We love our granddaught to pieces and would do anything for her. But what about us!!!! How do we live our lifes without the stress. Do we just put aside our feeling and deal with it??
I really could use some help. We are at our ends.
We are waiting to go back to court to see what the judge would say.
If we give her back, we feel like Kayla wont get the care that she needs and might not survive.
She right now has a 25% survival; the doctors don't expect her to live more than 2 yr.
We are so confused. hurting, mad and scared.

Tim