I need to know if an EMG/NCV of the affected lower limb was done in your sister. This would be able to depict if there is any injury
to any nerve
supplying that limb and the prognosis can then be clearly outlined. The key to outlining this problem is to note whether there is sensory affection only or if the motor nerves are also involved. Only then a proper management can be recommended. It is unlikely that improvement can be achieved with medications.