You have not mentioned whether your friend is a contractual (outsourced) employee. Denial of leave is illegal for any employee, whether regular or contractual. The principal employer is responsible for ensuring that the labor laws are implemented in earnest, notwithstanding the status of the employees.
Possibly, your friend is a contractual employee. It is possible that the employer, while making a contract with the manpower contractor, did not make provisions for additional manpower to cover for employee absences due to sickness or authorized leave. Now, they are depriving employees of their basic rights.
Please advise your friend to speak with HR. However, if your friend decides to take a confrontational approach, he/she could be terminated with just a day's notice. Is your friend prepared for this?
If your friend is not overly concerned about his/her employment, he/she may approach the labor officer of the area and explain the problem. However, this should not be done without first consulting HR.
Every other day, we encounter strange problems regarding the violation of labor laws on this forum. If what you have written is true, then kudos to the compliance of that company's HR.
Just recently, I provided a detailed response to a similar post. You may click the following link to understand why this situation is occurring:
https://www.citehr.com/423107-soft-s...ml#post1915976
Ok...
Dinesh V Divekar