I Have A 7 Month Old Child In My Care.

I have a 7 month old child in my care. She can sit for short periods of time with a boppy before folding in half like a rag doll. she has no muscle tone, is very tiny, and seems to have depth perception issues as well. The parents say nothing is wrong. I want desperately to help this child. Can You give me an idea of what it could be and what I could possibly do to help her.