You know how these brothers are absolutely smitten with the MC? Along with almost every character in the game?
Imagine how Solomon would tell the brothers this feeling of love in ABSOLUTE detail, and they don't understand what he meant UNTIL:
They suddenly look at MC one day with their eyes going wide, almost as if they felt they're heart jumping at just the sight of them, their eyes softening as their feelings are swelling up in their chest and go like— "oh."
And Solomon will stand to watch it, literally having mixed feelings when he saw the way they look at MC because it's just how he looks at MC too.
Full of love, and ready to accept MC's love, to the point where he's scared that he pales in comparison to the brothers.
He knows where he stands, and he knows that no matter the time and place, the MC will always choose the brothers.