I would recommend the Heilkunst system, which includes but is more comprehensive than homeopathy alone. Practitioners can work by phone and send remedies by mail, so your daughter could start right away. The success rate is very high for all sorts of chronic illnesses, and yes, many people with Crohn's have been treated successfully. Contact the Hahnemann Clinic for Heilkunst, http://www.homeopathy.com/clinic
It can take time to get to the root causes of the problem, but meantime the Heilkunst practitioner can help with managing symptoms while the deeper issues are being treated.