Cant find mister crowley in fall out 3?

ok i finished the quest but i als did the quest a whole lot be fore and this hasnt happen till now, i get mister crowley the keys and followed him out side so i could kill him but when i went out he was stuck in the wall in underworld and i just thought hed go get it later so i left adn it actually benn more that a year in the game cause it was 77 and now it mid 78 but i thought he would have came back now but he hasnt so i dont know what to do but if you can help me where he like a picture or any thoughts would be helpfulmight be