As @DanielPlaysInROBLOX said, where are the welds for the 5 head Parts?
If the head ‘falls off’ because the joint between the head and Torso is broken, your player should die (if you haven’t changed that property).
Is the 1 head Part with the other 5 Parts in it a transparent Part? If so then if it’s probably staying attached to the Torso.
Have a look inside the player (in the workspace, not in the Players service) when you play test.
Does the Head still show?