Honestly, what you're saying seems wrong (I think). Maxi wouldn't allow something like that to happen, and I also don't believe her father would interfere, because, frankly, from his perspective, their marriage is hanging by a thread since Riftan was supposed to marry Agnes (the Princess). He beat Maxi because she 'failed' to keep her husband by her side and he actually believes they might divorce, which is exactly what he doesn't want. So why would he allow a divorce? To let his reputation suffer? That seems like a rather foolish move, especially since Agnes knows Maxi and knows she isn't 'harming' her, so the Royal Family would side with them, not Maxi's father.
As for the first point (if I understand correctly, English isn't my first language), do you think Riftan sees her as a 'princess'?
Well, SPOILER ALERT FOR THE NOVEL:
He knows/suspects the truth. If I recall correctly, he was occasionally at her house/palace as a child and saw her father yell at her. He also sees her reactions, her stammering, and her panic fear of rejection
Never read the novel, but the manhwa clearly shows he does think she's a princess who never lacked food, dresses, jewels; and Maxi encourages that misunderstanding
The guilt of having Maxi at war, it alone would make him want to atone I think
Now, add the father trying to take advantage- im not saying the father will make them divorce, or will truly take advantage, but he might want money, he might want to make use of Riftan's fame
And if he did, it feel like both of them will have their hands tied- Riftan due to guilt and Maxi because she wants to keep the secret of how treasured she was
Of course, if that happened, it would be a good opportunity to force her to overcome her fear and come clean, if only to protect Riftan
Looking only at the manhwa, Maxi's father still has no reason to do that. Riftan has the royal family on his side, and while her father probably doesn't know everything (Does he know the King proposed marriage with Agnes to Riftan? I think that was the case, wasn't it? But he doesn't have to know they're "friends” xD and that Agnes is friends with Maxi now too).
So, let's assume he does what you suggest. I see it playing out in a way where the royal family steps in (and I see Agnes as the most likely person to do this) and sorts everything out. After all, she is also taking part in the war, so she understands Maxi + Maxi is a mage, so she can technically be at war because of that, and because of being a "nurse." So, frankly, I don't understand what grounds he would have to accuse them of anything.
And what about Maxi and that situation? Honestly, I don't know if that would make her speak up. She hasn't undergone the complete change that would enable her to do that yet; it's too early for that. Even if we assume all of this happens within the range of 50 chapters, I still don't see her telling him about it. She would probably be too terrified of the situation (just as you mentioned) (although, okay, regarding whether she would speak up, I admit my judgment might be wrong since I know what in the novel caused Maxi to become even stronger/braver, and that's when she told him about it).
In summary, Maxi's father is an ass, but if he's rich and "valued," he must have someone advising him (I assume XD), so I doubt he would do it considering all the elements I mentioned
Regarding seeing her as a princess, I might be mistaken because the manhwa and the novel are starting to blend together for me, but didn't he already mention that he used to visit the Croyso castle (I think that's what it was called?)? He didn't have to mention seeing her, but if he went there and said so, it's obvious he must have seen something. Plus, I know for a fact that he talked about someone he knew who broke into the castle just to see her, and I think he was referring to that person then. But if he didn't mention the first thing (visiting the castle), then you could actually think he sees her as the one and only princess, and he has a different explanation for her stutter (after all, he's stupid as f*ck)
He meant himself*
Riftan did mention visiting the castle
It was presented as the root of his love for Maxi, and it was never hinted that he saw what was going on
Even in his behavior it seemed like he simply fell in love, and never thought she was abused
The royal family doesnt know either, that she was abused.
Instead everyone sees her as this fragile protected girl, so that's why it didn't occur to me that they'd vouch for it being normal that she's at war
Like they might respect it, but would they think it wasn't wrong? I doubt it
Agnes is a princess through and through, but she received formal training, while Maxi studied hidden in a library and sneaked herself into the role of a nurse, the justification isn't exactly the same
So its like.... I get it, but I still think its a rather tricky spot she put herself in
Yeah, she got herself into a difficult situation, I'm absolutely furious with her myself for acting so foolishly (after all, she truly has no experience in such situations). However, let's assume we're in our world, in a country where everyone who can be is conscripted into the army, so even if you lack experience, you'll end up there if you have the predisposition. I think it's the same there. I'm not sure if Agnes sees her only as a delicate lady, but I believe she would understand her, especially when she found out that she is a mage. Maybe she would be angry that Maxi didn't go through training, but she would still side with Maxi. And as for Riftan visiting Cross Castle, it's very easy for me to guess that if he went there and saw her, he must have seen how everyone treated her and how she felt there. I even thought about it before the novel [mentioned it], but yes, his behavior doesn't necessarily indicate that. I still think that if her father wanted something from Riftan, he would lose that confrontation
However, I can understand what you mean; it's just less likely to me that it would happen that way
he already thinks she was raised as a shelter princess, and now, he'll think she ended up in war because of her
Seriously if Maxi's father wants to take advantage, saying he endangered her, they won't be able to refute