The Penultimate Peril discussion

When Sir refers to Charles as his partner, does he mean something else? Charles seems to have no authority in running the lumber mill. They share a hotel room, wear matching pajamas, go to the sauna together, and bicker about each other's behavior like an old married couple. Charles flat out tells Sir that he cares about him. During the fire, they hold hands. I kind of get the impression that these guys are partners of another sort (not that there's anything wrong with that).