Manfred supposedly drowned next to his computer, but hidden messages throughout Crow 64 suggest that Manfred is somehow still alive.
Maybe it has something to do with the eternal rebirth system that is mentioned from time to time, maybe he died drowning but the game keeps him here somehow, maybe that's why it says that "every year you drown" indicating that he is always drowning but not completely, what I wonder is, who left these messages, was it Manfred or someone else?