He's running a classic gimmick strategy, and the the trick is to make it hard to table you. Basically, run tons of durable units and vehicles (Storm Ravens and Land Raiders) and fill them with super tough units (Plague Marines, maybe Termies?).
Also, when they leave the Drop Pods, his units will all be in one place, meaning you can severely punish him with a proper counter-attack. Take units that can output serious damage on clustered enemies (Obliterators, Defilers), and also plentiful anti-MEQ (Plasma Units and AP 3 templates).
Another thing to keep in mind is that even though his Drop Pods won't scatter, you can still present him with situations where he can't place a unit close enough to kill his target. An example would be baiting him with something expensive and powerful or to create a very strong formation where he can't show up behind you. Hordes will have an easier time of this, but making clever use of walls will save you. Also, since they still are arriving from Reserves, messing with them can be a nice route to take (Comms Relay).
I'm not sure what you meant by that last sentence though; he's a player who emphasizes army synergy over unit strength? Because that's what any good army list should be focusing on anyway, so I don't see his point.