I've been playing to the game with the patch. In the part of the slaughterhouse where you must open the gate to let Double H through, he simply dissapears. In the later parts of the slaughterhouse, you can hear the sound clips of him talking, however, his model is invisible. He is also not present at points where he is needed to progress. Has anyone had a similar problem or know a way to fix it?

I'm having the same problem!! I have no prior save so I can't redo the part and see if it happens again he dissappears exactly there, please anyone help?

He doesn't actually dissapear, he falls down the shaft and hold on to something and continues talking to you and then falls down further then you meet him later.