My Grandaughter Is 24 Months Old, And Has Been Diagnosed

My grandaughter is 24 months old, and has been diagnosed with Fetal alcohol spectrum disorders and we are currently just getting court orders for medical care and custody hearings are coming up shortly that should make things move along more swiftly with getting her care. This weekend while here she was when experiencing any frustration hitting her head with her fists, slamming her head into furniture and clenching her tiny little fists. We are so focused on getting her wieght up, she is still under the 5% range, and she is exceptionally loving and very quick to learn, that this shocked us. she has tremors in her extremities, began in her hands at 5 months, has since progressed gradually to her arms and now her legs. Is the head hitting an issue related to FAS disorders that I can reverse?