Hallucination is actually only a problem/of interest if you are around other people because it's about what you see/experience like/unlike the others around. If you hallucinate a red light and stop and foul up traffic, people will be honking at you, swearing at you, running into your car and/or causing car accidents, etc.

Your little man's ex-wife lives with me and told me about him.

I think of the classic bugs-on-skin hallucination that can be caused by some physical illnesses and other things besides "pure" psychiatric ones. It's not something you want and/or it bugs (sorry for the pun) the people around you, causes them a problem.