Confirmation Process for Employees
There is no automatic confirmation unless otherwise specified in the company's standing order or appointment letter. If it is stated in the letter of appointment that the employee will be confirmed only when communicated about their confirmation, then that is the process to follow.
There is no law preventing an employee on probation from taking leaves. If they have been working for more than one year, they should naturally be eligible for Earned Leave (PL) in addition to being eligible for casual leave and sick leave, similar to other employees of the company. Even a notice and compensation for retrenchment is required if you want to terminate their service for any reason that allows for retrenchment. (Please note that this applies to retrenchment following section 25F or 25N of the ID Act.)
Though a probationer can be terminated without assigning a reason for termination, it will be illegal if that termination causes a stigma. Since the employee has been working with you for one year and you have not appraised them or found any negative issues, termination would cause stigma. Therefore, if you have not changed the status of the employee, you should do so now. Obviously, you should collect feedback from their reporting officer, but only for the sake of complying with formalities.