There is definitely a correlation between Sarah's headaches and the conversion of the Hindu children. I know by experience. When you mess with the devils territory there is a price to pay. The Apostle Paul and his difficulties come to mind. I struggled with my boys playing video games for several years. It began innocently then gradually took over there lives. Finally I took it away while they were gone. I immediately became extremely ill for 2 weeks. I could barely get up, I had a high fever, puked and had diarrhea when no one else around had any flu in the middle of the summer. My urine burned like fire. I became dehydrated. My heart was racing. I finaly got on the phone and asked my prayer partners to pray. I felt quite close to death.
 
I understand your desire to seek medical help. But if the doctors have not found anything and this started when these Hindu kids where converted you are barking up the wrong tree. You need people who know how to pray and deliver your daughter from this demonic attack. You need to bind satan and pray for the ex hindu kids parents too. We bind the strong man before we take his goods.