This episode was, of course, a key turning point in the narrative of the Crusader Dad canon. While up until this point the series had been mainly a slice-of-life drama involving the father struggling to turn his son to a righteous path of study, combat training, and the true faith, here we see the very real consequences of the conflict that has always been stewing in the background. The conflict the father was always preparing his son for - the day the weebs take the holy land. We finally learn that the father is not disgusted by his son's tendencies toward anime due to simple personal preference, but because affiliation with Japanese animation is a key characteristic of his mortal enemy. Knowing this, his extreme acts of aggression to discourage these tendencies can almost be understood.
However, the Father himself seems to recognize the fact that his repression of his son's tendencies may have done more harm than good. Notice at 0:12 how the son's initial hesitation about taking up his father's sword are not for the seemingly obvious reasons: that his combat skills are considerably worse than his father's, or even that he agrees with the weebs due to his own love of anime and "related media". No - his stated reason is "I'm a heretic", implying that the only reason he should not fight is because he is unworthy. This fact has been internalized within him over an unknown length of time as a result of his father's lectures and punishments.
[08:33]
And then the father says three simple words - "It doesn't matter." These three words are the antithesis of all his teachings up to this point - that even a heretic can be worthy if his heart is pure. And the father knows that his son's heart is pure, despite his heresy, despite his consumption of anime, despite his lack of diligence in study and his lack of talent with blade and firearm alike. The son's further hesitation at 0:19 seems, on the surface, to be a moment where he is considering refusing his father out of cowardice, lack of belief in the cause of the Crusaders, or as revenge for how harshly his father has treated him in the past. But the truth is that he is still doubting himself, despite his father's words. The father understands this, and his final nod before collapsing is meant to break the last barrier in the son's mind, a barrier that the father no doubt sees himself as being responsible for building up - a lack of self-worth brought about by a vicious cycle of disappointing his role model. By nodding, the father is silently admitting that his son's heretical beliefs and degenerate actions are simply a part of who he is - and they do not make him any worse of a man, or of a son. Though the nod says nothing directly, it says many things implicitly:
"Despite our differences, you are still my son and I know you can do this."
"Believe in yourself, as I believe in you."
And with that barrier broken, the son can confidently pick up the sword - a European sword, mind, not the katana he had previously been seen wielding and is doubtless more comfortable with, turn off his anime, and like he has done so many times before, scream at the top of his lungs. But this is not, as so many times before, a scream of fear. This is a war cry, the roar of a righteous crusader.
[08:33]
https://***.youtube.com/watch?v=RyKiKTs9hjc