Is it permissible, from a Sharia perspective, for a merchant to employ his wife – with the intention of benefiting in the future from a work cessation grant paid by the responsible authorities – while the applicable law obliges him to declare her and pay a monthly sum on her behalf for medical treatment compensations, the work cessation grant, and other benefits?

If the entities insure the worker or invest the amount in usurious banks, it is not permissible to pay them the amount when there is ease and choice, because it is assisting in forbidden insurance and usury. However, if you are forced to pay it such that you would incur severe harm by not paying, then there is no blame. But neither you nor your wife are permitted to benefit from the insurance amount except for the portion you paid. Any excess should be spent on the welfare of Muslims. If the entities do not insure and do not invest in a usurious manner, but rather take the amount and compensate the worker upon retirement or damage, then there is no harm in that. And if they give more than what was paid, the increase is considered a donation.