As suggested by learned members:
You may find the rules pretaining to medical leave under leave rules.They may be exhaustive or silent on your query.
Employee can avail medical leave, paid/unpaid as per terms of appointment and as per leave rules of the company.
Exceeding the specified limit if any,it shall be discretion of employer .
Medical leave may be extended upto a reasonable period.
The medical condition,diagnosis of the treating doctor and review by the doctor who has recomended the bed rest/leave or has extended the bed rest/leave and internal opinion of the company shall determine the further sanction or action by the company.
e.g a patient of fracture femur shaft and subsequent interlock nailing operation/procedure , may require leave since he/she has to use walker for some time and may be adviced prolonged leave say uoto 3 months.
Company should communicate properly about further sanction of the leave.
Company can ask for examinatin by doctor appointed by them, or civil surgeon as per their policy,convictions,but should express properly.
Employee should also be fair and should keep the company informed about developments/improvements in condition.
Termination during proper medical advice for rest/unfit to join duties period shall be a good reason to contest the termination.