Legally and professionally company should not indulge in such practices.
Since the Head of the company wants the things to be done his way he has probably chalked out eh course for making the things happen his way.
If entry to office is prohibited without any previous communication and legitimate reason employee can lodge complaint with Good offices of MD, Chairman and also Union (if any) and for that matter with local police.
Usually employees who are to retire do not wish to enter into any conflict, altercation and would like to retire peacefully.
A sensible employer (Promoters, Owners) would not push their inner wishes down the throat and would value the vintage and experience of employee.
Apparently the new head want old ones to go and new ones to come.
Your father by virtue of his experience can settle his future ventures.
Probably it is time to hang the boots of this company and bid farewell.
Let him go thru his appointment letter and resign in line with terms and conditions of his appointment. He may tender resignation or notice of resignation as deemed fit. He should avoid any conflict and should not leave any room for the company to charge him on any count.
He can settle the matter with new head by offering resignation and getting a peaceful and smooth completion of exit formalities and payment of terminal benefits.
If your decision is checkmate the new head, your father may approach a competent and experienced service lawyer, and give inputs in person and checkmate all ill efforts of new head. Your father may request the promoters/ owners to transfer him to sitting job.
Gratuity can be forfeited only in case of
Payment of Gratuity Act, 1972
Section: 4
Payment of gratuity.
(6) Notwithstanding anything contained in sub-section (1), -
(a) the gratuity of an employee, whose services have been terminated for any act, wilful omission or negligence causing any damage or loss to, or destruction of, property belonging to the employer, shall be forfeited to the extent of the damage or loss so caused.
(b) the gratuity payable to an employee may be wholly or partially forfeited] -
(i) if the services of such employee have been terminated for his riotous or disorderly conduct or any other act of violence on his part, or
(ii) if the services of such employee have been terminated for any act which constitutes an offence involving moral turpitude, provided that such offence is committed by him in the course of his employment.
Valuable advice of learned experts/members is sought.