Once declared unfit to work, your friend can't do anything about it. It will be sooner rather than later that she should be sent back to her home country. Being declared UNFIT by Rumailah hospital means that she can be a threat to public safety because she could be infectious, if not now then on a later date. Not having a history of TB, meaning no symptoms, could not mean that she did not get TB because she can be affected without showing it.