What is the ruling on describing Christians as brothers and congratulating them on their holidays?

It is permissible to describe disbelievers—such as Christians—as "our brothers" if the intended meaning is brotherhood in lineage and humanity, citing Allah's saying: "And to 'Ad [We sent] their brother Hud." However, if the intended meaning is brotherhood in religion, then this is not permissible because their religion is either distorted or abrogated. Allah the Almighty says: "And whoever desires a religion other than Islam, it will never be accepted from him, and in the Hereafter he will be among the losers." Similarly, it is not permissible to congratulate them on their holidays.