What would you do???

I have a very complicated family dynamic . My husband and i have been raising our 5 year old granddaughter ( my daughters child) for the past 4 years. Several months ago we thought my daughter had matured enough to raise her daughter with our help if needed(since my daughter is raising her 2 1/2 year old son) however my grandaughter only wanted to stay in her room while at my daughters and had lost weight ( we could see spine and ribs) my grandaughter is very active, outgoing and impulsive but most of all we noticed a decline in her personality like her spirit was gone . Since we took her back (we have legal custody) my daughter has only seen her (by her choice ) 2 times since the summer and in the last 6 weeks has talked to my granddaughter once on the phone (we live in the same city). My question is what to do about Christmas?? Grandaughter wants to see brother (she is concerned) and really misses him ,wish there was something I could do to fix situation .Anyone with answers?