Dear Tiwari,
While sincerely sharing your grief, I would like to convey my views about the entitlement of your deceased BiL for compensation under the Employees Compensation Act,1923 from my own experience as a Commissioner under the Act.
The definition of employee under the Act stands as of now:
"Sec.2(1)(dd) " employee" means a person, who is -
(i) a railway servant as defined in cl (34) of sec.2 of the Raiways Act,1989, not permanently employed in any administrative district or sub-divisional office of a railway and not employed in any such capacity as is specified in Schedule II; OR
(ii) (a) a master, seaman or other ------ of the crew of a ship
(b) a captain ----- of an aircraft
(c) a person recruited as driver ----- in connection with a motor vehicle
(d) a person recruited for work abroad ------- --- ---; or
(iii) employed in any such capacity as is specified in Schedule.II, whether the contract of employment was made before or passing of this Act and whether such contract is expressed or implied, oral or in writing; but does not include any person working in the capacity of a member of the Armed Forces of the Union; and any reference to any employee who has been injured shall, where the employee is dead, include a reference to his dependants or any of them; "
So, what is important for entitling a person for compensation for any employment injury or death due to an accident arising out of and in the course of his employment is his employment and its capacity as set out in Schedule II of the Act which contains the list of persons, who subject to the provisions of Sec.2(1)(dd) are included in the definition of employee.
It is to be borne in mind that the list is not illustrative but exhaustive.
Unfortunately, I am not able to find your deceased BiL's nature of work in the list.