Dear Deiveegan, what's your confusion in this case of unauthorized absence? The employee has, in the first place, breached the contract of employment by absenting himself without prior approval of the employer or any intimation from his side thereafter. Eventually, the employer is relieved of his responsibility to pay him wages as per the contract of employment. Hence, the payment of salary to the employee for the period of his absence is out of the question.
Secondly, the act of unauthorized absence by the employee is misconduct, and his remaining so for long without further intimation, if any, tantamounts to abandonment of employment.
Therefore, it would not be sufficient on your part to just consider him as a dropout and remove his name from the roll. You have to take disciplinary action against him as per the Standing Orders or the Service Regulations applicable to him by framing definite charges, conducting a domestic enquiry, issuing a second show cause notice, etc., addressed to him at his last known residential address available at your end, and finally terminate him.