What is the ruling of Islamic law on establishing a cooperative fund to financially support members upon their first marriage, by collecting a specific amount from each member a month before the marriage of the eligible member, with the heirs of the deceased losing the right to reclaim what he paid, and obliging the member to pay even if he leaves the company or the country, and exempting the unemployed from paying even if he later becomes employed?

What the enquirer is doing is a donation, not a loan, so it takes the ruling of a gift. If the participants agree to the conditions, then there is no objection, based on the Prophet's (peace be upon him) saying: "(Muslims are bound by their conditions, except for a condition that makes a lawful thing unlawful or an unlawful thing lawful)." The conditions mentioned do not make a forbidden thing permissible nor a permissible thing forbidden, so they are valid and there is no objection to them.