Is the questioner considered to be severing ties of kinship, given that his brother has not spoken to him for five years?

Maintaining kinship ties is obligatory, and severing them is forbidden. It is your duty to maintain ties with your brother, even with the lowest degree of connection that removes the estrangement, such as greeting him by phone or messages. If you do what you can and your brother does not reciprocate, then you are not considered a severer of kinship ties. It is incumbent upon those relatives who are aware of the estrangement to strive for reconciliation. You should endeavor to maintain ties with your brother and be good to him, even if he cuts you off, for "the one who maintains ties is not the one who reciprocates, but rather the one who maintains ties is he who, when his kinship is cut off, he connects it." If you maintain ties with them and they cut you off, and you are good to them and they treat you badly, and you are forbearing with them and they act ignorantly towards you, then "if you are as you say, it is as if you are feeding them hot ash, and you will continue to have a supporter from Allah against them as long as you remain upon that."