What are retirement benefits in private ltd co.

Hi,

I am working in a private ltd co. since 20 years in hyd as office administrator. now i am suffering from multiple neuro disorder (Dyskensia). Presently drawing salary / month is rs.46000. now i am not able to continue service. i need suggestion/advise, i have a good reputation in company. Please let me know the proper way to convey my boss regarding my retirement. and please tell me the benefits i can claim from the company like gratuity and others. so far i have not entitled any benefit since joining.

thank u