shazzakh

Hey everyone, forgive me if I put this thread in the wrong forum section, but I cant seem to find Fawkes after I completed the main quest of Fallout 3. Basically I used him as my mule for heavy items and now he's gone. I've looked in the museum of history, my megaton home and even the project purity area, but he is nowhere to be seen, does anyone have any idea where he is? I've got all of the DLC's installed, a long with the FWE3 plugins. Thanks