Can Employer Relieve The Employee From Duties On The Basis Of Old Resignation

Hello Everyone, One my friends working in ABC company got a good offer from XYZ company in September 2019 and he resigned to the job of ABC. ABC’s management requested him to reconsider his resignation with a salary hike and he rejected the offer from XYZ company he continued to work with ABC (though he did not withdraw his resignation). Subsequently, during December 2019 my friend’s son was admitted to hospital and who was covered under group insurance. My friend claimed insurance amount for the expenses made against the treatment of his son. Which is being processed by the Insurance Company. During the same time differences arose between my friend and his manager and his manager started torturing him and started asking him to resign (orally). My friend kept on saying that I will resign once his insurance claim is settled. However, today (22.01.2020) when he went to office, his e-mail was deactivated. After inquiring with the manager he came to know that he has been relieved with effect from yesterday (21.01.2020) on the basis of the resignation submitted in the month of September 2019. My query is, whether a company can relieve the employee on the basis of a resignation submitted almost 4 months back and also whether this would affect his claim settlement with the insurance company