Are a brother and sister considered kin to each other, and do the same obligations and consequences apply to each of them regarding maintaining kinship ties?

The kin whose ties must be maintained, according to the preponderant opinion, include any two people between whom marriage would be forbidden if one were male and the other female. These are: fathers and mothers, grandfathers and grandmothers, brothers and sisters, children and their descendants, and paternal uncles and aunts, and maternal uncles and aunts. It is obligatory for a brother and a sister to maintain ties of kinship with each other, and cutting off these ties is forbidden, as the religious texts encompass both genders. Maintaining ties of kinship is achieved through what is customarily recognized by the people of the land, such as visiting, communicating, and giving gifts, according to one's ability and custom.