Your problem appears to be more arising out of leave policy. Do you have a proper leave policy? If yes, have you defined the eligibility of the leave?
Leave policy apart, the problem lies with the Manager who sanctions the leave whenever his junior approached for the leave. In the leave policy of most of the companies, it is stated clearly that "leave is not an entitlement of the employees but it is a privilege". Whether to approve the leave application or not is the discretion of Manager or HOD.
Employee's leave might have been sanctioned by the Manager but if he does not have sufficient leave balance then did he apply for "Leave Without Pay" (LWP)? If yes, then are you deducting salary for this absence?
Lastly, please note that there is no plural for the word "leave" if it is used in the context of the absence from work. Therefore, you may write as "number of days of leave".
20th March 2019 From India, Bangalore