Thanks for writing your query.
You sister needs urgent clinical examination and investigations.
Get her investigated for :-
1. Complete Blood Count
2. Urine examination
She can be given paeracetamol 500 mg for fever
and bodyache, Domperidone
10 mg once a day along with antacid Omeprazole
20 mg for vomitting.
Also take care of her hydration and diet.
Give her healthy diet including fresh fruits and vegatables.
Proper rest will help her to recover soon.
Medical management can be planned according to the reports of the investigations.
I would suggest that get her examined medically.
I hope this is helpful to you.