No matter whether Serafe eventually marches south or not, Horn is going north, so for the moment he's ignoring the Royal Court's movements.
As for military affairs, the staff group and the Chief Priest are handling them, and a combined-arms war army at this level inherently has the capacity for autonomous action.
To put it bluntly, the Imperial Army fights like Mount & Blade, the Royal Court's army fights like Total War, while the Holy Alliance fights very much like auto‑chess.
But that doesn't mean that, as supreme commander, Horn can just sit around doing nothing.
Just as he usually teaches the other war‑army commanders and Battle Commanders: do your own work yourself.
As a commander, if you don't personally get a prior grasp of geography, roads, local conditions, logistics, and so on, and only rely on others' eyes and mouths, you'll always be one layer removed.
