I'll say it plain and simple because I'm not good at storytelling but I believe Oh-father is controlling homelander. Kinda some spoilers.
>!1. When he screeches early in the season during congregation, homelander "sees the light", it changes him and gives him an epiphany, a golden moment/calling. We don't explictly know the breadth of his powers, he may be able to influence or induce visions which also might be commentary on how powerful the church is when manipulating/controlling people (or I guess was at the time of writing).!<
>!2. Church is going broke -> he needs more money -> he is assumed to be the head of the DCA, so he's really on board for pushing this agenda so he can remain rich and at the top.!<
>!3. Was he really just loading up some normal breast milk for homelander or is there something in there? More and more we're seeing homelander fall prey to stuff like radiation, or the gas that knocked him unconscious, who knows what he could be adding to the milk.!<