Extension of child care leave application denied by school

I m a teacher in govt sponsored h s school in wb.my 6 yr old only child was diagnosed with malignant tumor in heart in August 2017.she underwent open heart surgery n started chemotherapy for cancer in mumbai.i applied for ccl.school sanctioned me 120days as it is the extreme limit as per govt rule.my child's chemotherapy continued upto april2018 hence I requested school to extend my ccl.school denied n put me on medical leave without my concern.ccl of 735 days is meant for taking care of the child by working mothers.now in my situation where my child is fighting with cancer can a challenge the 120days.ccl limitation at a time.since the leave is for the child bt for this kind of limitation in such an extreme situation like me it's useless.plz advice