From the information you’ve given it appears all of your sister’s numbers have trended downward the past 2 months. The platelet level of 117 is below the ‘normal’ low of 150 (150,000). If it continues to lower she may experience prolonged bleeding from a cut or nosebleeds. Has she been having more bruising than usual?
How about her general health right now? Is she having any symptoms of shortness of breath, headaches, fever, night sweats?