I understand the question like this: You have selected/issued an offer letter to a candidate, but he requires a few days' leave immediately after joining. Your company policy states that an employee is allowed to avail of leave only after six months or upon confirmation. He knows that the leave will not be granted but hopes to get it on a loss of pay basis. If you refuse to give him leave, he will join your company only in May.
Even if you allow him leave on a loss of pay, you will benefit from him only in May 2024. Let him join in May after he has resolved his personal emergencies for which he is asking for leave. This will help you maintain your HR policies, ensuring you don't dilute them for one employee. Also, why would you put an employee on the roll just to give him leave? An employee on leave is equivalent to an employee in service. Legally, once an employee joins, he is your employee. Suppose he does not return; you will end up sending show cause notices, termination letters, etc. Do you want that to happen?