I don't think he's setup to work on the DCL. He picks up RF transmissions to get his info, and I don't think the boats have that. But if you go to the Pal Mickey page on Disney's website there is a list of places he works. Pal Mickey Page
He'll work to play games on DCL, but as of now there are no interactive features like there are in the parks.
I can't imagine how much you would want him to do on the cruise ship though- as there is very little wait for anything, and character appearance times are in the Navigator daily.