All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Whoever sponsors an orphan and treats him well shall have a great reward. We should stress here the difference between the commendable sponsorship of orphans and adoption which is prohibited.
Giving Zakah to an orphan whom he voluntarily sponsors is allowable. The sponsor may spend on him out of the money of Zakah or deposit it for him in an Islamic bank savings account, thus transferring it to the ownership of the poor orphan.
Allaah Knows best.