Ms Seema,
to add,
does your company have a high attrition rate, a hire and fire policy, victimisation of managers, low morale, bad managerial and hr practices, etc it is more a time for corporate introspection - ofcourse you could be personally helpless unless this is an isolated case and you have a professional progressive introspective culture where management is open to take corrective cultural initiatives in today's age of enlightened hrd culture.
may be the next employer has assured him of all support while joining the organisation and he has taken a calculated risk. some companies do not relieve a person timely or settle his accounts promptly even though a thorough resignation has been submitted finding excuses to extend his stay to complete assignments etc as a matter of right over the employees. did he have any genuine grievances or were his relations with the top management or his boss impaired for any known reason. this may have a demoralising impact on the managers and employees down the line.
let some very senior company official have an out of the campus transparent discussion with him at a hotel/restaurant assuaging his feelings. since he has already joined elsewhere help can be requested on critical information or pending matters visiting the office in the evenings or on holidays and keeping the communication lines open and friendly. he could be requestd to hand over the files/documents he has to an authorised person nominated by the company, simultaneously handing over the cheque for his dues after deducting the notice pay due to the company as a matter of policy. invite him for a farewel party one evening where the misundersandings leading to the situation could be clarified assuring other managers of a transparent enlightened management able to handle the situation coolly preventing further damage of morale in the organisation. hope all this is possible - could enhace the corporate image and the employer brand value to be repaired and encashed, atleast a theoretical possibility if one would like to learn to handle emotions rationally and act wisely enough. hope this makes atleast an interesting reading for ourselves.
in one company a very senior ceo joined a competitor attending his exhibition even before he had officially left the company which the MD did not like. his dues were cleared, invited to the office and handed over - over a boque of flowers and some icecream in the MD's office, avoiding a group farewel to avoid any further embarrassments that could crop up. thus things could be handled amicably to the extent possible.
earlier it was labor/industrial relations handling matters legally through legal documentation and legal games, now it is human/employee relations making the workplace a better democratic place with proactive people oriented culture leaving no room for such incidents as above a senior person leaving without intimation which does not speak well for the company culture too with a need to handle the situation with soft options possible reducing the cultural damage - deploying the much talked of soft skills in practice. unless the facts warrant a legal punitive action beyond doubt.
hope this helps academically atleast.
regards and best wishes,
kshantaram