Dear Priya,
Because of his unauthorised absence , if he falls short of completing 5 years' of continuous service which means during each year of his stint, he should have put in 240 days' of uninterrupted continuous service as defined in the Act , then in principle , he is not eligible for gratuity.
However you need to share his attendance particulars during the entire period of 5 years' service or more if any , to advice you accurately.
Regards,
Vinayak Nagarkar
HR- Consultant.