You and your god-daughter are in my thoughts. There are few things harder than looking after an ill child, The anxiety and the sense of powerlessness can be huge, not to mention the loss of sleep, financial implications, etc, etc. Strength comes in many forms and you are showing the kind that comes from the heart.
My son, who is now eleven-years old was born with autism, life threatening asthma and a seizure disorder. There are two pieces of advice I can give you:
1) Look after yourself
You can not be of use to anyone else if you neglect yourself. You can do it for a short time, but over the long haul you need to be in good shape yourself. Call on whoever you can to give you an occasional break to get some sleep, have a break or just be you. Eat well. Sleep when you can. And find at least on person, family, friend, therapist, clergy that you can unload on.
2) Become the child's advocate
Learn everything you can about cerebral palsy, its diagnosis, implications, treatment options, etc. Find online forums for it, etc. Don't be afraid to ask questions and to seek second opinions. Never shrink from following your gut: if you think the child is sick or in need of help - even if you're not sure - do not hesitate to call the doctor, go to the ER, etc. I think in 11 years we've had one false alarm and at least half a dozen averted crises because of this.
I was very, very lucky to be able to assemble a team of people around my son who have achieved remarkable results. Now a child we were told would probably never be able to run, speak properly or be able to succeed in school is an exceptional tennis player, loves playing touch football, rides horses, thrives in school and is turning into a very capable dog trainer! It takes the work of half a dozen people to keep him in school, but he's doing great. We are very fortunate to live in a place with exceptionally capable public schools, but I realize also that because the school and my son's doctors, therapists etc know that his mother and I watch our son's progress like hawks, stay on top of medical developments, etc, speak up when we have concerns and gush thanks and praise on his team when they get things right, our son he is getting everything they can offer.
I wish you and your god daughter all the best. Please feel free to email me any time.