Howard Dean is the answer to that. Regardless of what you think of Dean as a candidate there is no denying he impact on activating citizens to get involved and empower themselves. Find his "You have the power" quotes and find examples of DFA members and groups taking that power, running with it, and making a difference.
Let him know he is not alone. One of the strongest messages I heard in 2003 when working on Dean petition drive and primary campaign was Democrats and Liberals feeling like they were surrounded and all alone in their beliefs (resulting in those powerless, hopeless, apathetic feelings). One of the greatest joys was to see people light up and get energized once they discovered they were not alone and that there were specific actions they could take to make a difference. Find examples of this (particularly close to home to him) and show him that it is not hopeless and that citizens... citizens like him... are taking back their government... running for local office, picking their own candidates and backing them, etc.
Empower him.
just being with those people - having that sense of community - really does wonders.