By setting him as proxy you are allowing him to control your witness votes in full. So you vote the way he votes. As long as he is voting for himself as witness, then yes, you are voting him as witness. You are also voting everyone else he votes along with him.

Setting a Proxy is basically a blanket of trust, you trust the person yo set as Proxy and their judgement on who the best witnesses are over your own judgement, so you give them your voting power. Geek is sure to have a set of Witness Votes that are working for the platform, so a very worthy Proxy.