There's the option for one of the other PCs to talk to them, but in the event that they don't, you can assume Watanuki would alert both of them. Especially once Sunday's stuff finishes up, since what's going to happen relates to the curse and curses in general are pretty relevant to everyone at the shop. Watanuki would be like "okay, time to call in everyone and see who can help with this."

He would also open a doorway to Hayes mansion for anyone who wanted to go there to help in person.