So I been thinking about this for a while and shared my theory on Hopes server. I might as well go ahead and share it here as well.
Hopes is clearly writing on a different level than most and already has a unique story in mind. I don't see Hopes as a person who does things without a reason, example Netorari or Friendship routes, or not including a Harem tag. These things all have meaning in my opinion. Possible Spoiler territories up ahead.
Antonio has been made out to be a guy buckling under stress for a while now. He's clearly more emotional than the others and has a much harder time dealing with everything. He's showed us major failure in planning the attack, one Grace was bold enough to fix on her own. Now we know he's even failing at home in his bed with his wife. This leads me to believe that Antonio isn't cut out to lead.
Wilfred is a very well organized character with a vast information network and commands great influence. His goal is the survival of the family. So basically he knows about Antonio, and I'm betting he know's about MC and Isabel.
So why is MC still alive? Why hasn't Wilfred informed Antonio?
My theory is that it's because allowing Antonio to find out on his own will cause a future conflict with Antonio that forces him to show his hand and tests the MCs importance. Antonio can't let what's going on stand, not really and MC is needed to the family for one reason or another. Antonio will create conflict with the MC, which will ultimately end with the MCs importance over riding Antonio's feelings. Keep in mind. That tag was Netorari and he was labeled as Bi. Antonio is still in love with his wife. MC taking his girl is a conflict that will have to be resolved. That being said Antonio will show everyone he isn't fit to rule which with Luna's state of mind, MCs not part of the family, leaving only Grace. The one person Wilfred believes is far more capable than everyone else. She is someone he can see running the family. I think Wilfred isn't saying anything because he wants Antonio to show everyone he can't handle it or worst case scenario end up dead in a fight against MC.
Now I get my theory isn't fleshed out, full of lots of holes and leaves a ton of place for MCs relationships with the others to be ruined. At this point only the mother would be what kept MC alive and I'm certain even that would be by razer thin threads. Yet to me this still makes sense. Now there is more conflict, more reasons to push Grace forward, more reason for the MC to dig into his current position and more reason to rebuild and ultimately become closer to all of the family members once more and begin making your true choice for a love interest.
But hey that's just a theory. A SlayerRaven Theory!