From what we could see in the preview the enemy kataphract this time seems to be able to create a sandstorm around itself.
-) Sandstorm has a LOT of force behind it, enough to take a terran kataphract apart as soon as it enters it
-) It's a powerful storm, so bullets aren't gonna hit anyways
-) Storm clears any traps hidden on the ground (such as mines)
-) Attacks from above
-) Visibility through sandstorm isn't really great either
-) Use of explosions to temporarily clear out the sand to land a hit (shoot a grenade into the storm, then shoot into the explosions right away)
-) Sand makes wind direction visible, Inaho may be able to calculate a trajectory which would allow him to hit the kataphract.
-) Fast and heavy ammo. For example the ammo used in the terran kataphract sniper rifles. The heavier and faster a projectile is, the less it gets influenced by wind
-) Deucalion. The Deucalion could just blast it apart with its main cannons or shoot some missiles at it directly from above
Remember that this is just some speculation based on what was observed in the preview