What is the legal ruling regarding a relative working in a restaurant in Israel that serves alcoholic beverages, knowing that he has no other means of livelihood and observes his religious obligations?

It is not permissible for your relative to distribute alcohol to restaurant patrons, as he would thus be a pourer and carrier of it. The Prophet, peace and blessings be upon him, cursed in the Hadith "alcohol, its presser, the one for whom it is pressed, its drinker, its carrier, the one to whom it is carried, its seller, its buyer, its pourer, and the one for whom it is poured." He should repent to Allah and increase his acts of seeking forgiveness and righteous deeds, and know that Allah has guaranteed provision for whoever fears Him, in affirmation of His, the Almighty's, saying: (And whoever fears Allah - He will make for him a way out and will provide for him from where he does not expect).