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.
If your cousin’s salary and the money he inherited do not remove his poverty nor satisfy his need, then there is no blame on you to give him from the Zakah, and after that you should not ask how and in which things he spent it. What is important for you is that he is needy.
Allaah Knows best.