His list must've been:
Inquisitor Coteaz - 100pts
Henchmen Warband w/ 3x Servitor + Plasma Cannon, 8x Psyker - 140pts
Henchmen Warband w/ 3x Servitor + Plasma Cannon, 8x Psyker - 140pts
Henchmen Warband w/ 3x Servitor + Plasma Cannon, 8x Psyker - 140pts
Henchmen Warband w/ 3x Servitor + Plasma Cannon, 8x Psyker - 140pts
With 90pts worth of something else included.
Whilst it's a bit of a pain to start with, everything bar Coteaz is BS3, T3, and with a 5+ or 4+
AS, and the longest-ranged weapon is 36".
He seemed to be doing it right, but what troubles me is this:
Mind you he failed a few of the psychic test to cast the blast attack he still got the majority of them off.
If you just mean he failed, then fair enough, but if you mean he got PotW, then every psyker in the unit is affected, and they all die due to lack of an invul.
A good counter to the list would be dropping a Furioso with a Heavy Flamer in next to a unit and torching them; return attacks will either be a Psyker's attack, and thus whas a good chance of scattering off and doing nothing, or plasma cannons, which can only glance his shiny FAV13. If he survives the turn, awesome, you can charge in somewhere, if not, then it doesn't matter much, because the damage he and the drop-pod can do will more than make up for it.
His Psykers can never use anyone elses leadership for their attack, so he's testing on Ld8. A Psychic Hood somewhere should stop most of them, and Fear of the Darkness can force them to make an
Ld check on Ld6, and possibly run off. Shield of Sanguinius would also give you a chance of surviving incoming fire.
Giving your squads flamers for when they drop in will help remove any psykers, and might even roast a servitor or two.
If you don't want to use a Furioso, you could always use a Regular Dreadnought with a heavy flamer and a
TL Heavy Flamer/Heavy Bolter/Assault Cannon/Autocannon (the autocannon only if it's glued with that weapon, the first 3 are more efficient against this list); he's cheaper, and can have a more efficient loadout, but is more prone to return fire.