The salts in the water would be enough cleanser for right now. She didn't want to point anything out just then and have him put added stress onto his arm. And if he felt clean, there was no harm.
"You are very welcome." It would give her something, someone, to think about other than mourn her eldest son. She would not let it show, the only one that would know would be her youngest son. And perhaps Katherine's wolves. "You know, instead of bringing it to me, I think I'll use this moment to show you how a few things work." For instance she leaned over and pressed a button beside the faucet and the water began to drain. "Towels are in that closet." She pointed at the small door between the tub and the shower. "You can leave the used ones anywhere you like, there are little mechanisms that will come clean things like that up. Same goes for your dirty clothes, you will find them fresh again the next day back in the closet. The only thing that we will have to care for is your armor." She lead the way into the main room again, before pausing. "Do you need to know how any of that works in there?"