I've told the following story a couple times over the last few years. It's scary to some people, so I generally choose my audience, but since no one actually has to read this, consider this a warning if you scare easily. Maybe I should have saved this for Halloween, but it's a story that's fun to tell so here goes.
One thing you hear now and then about autistic children is that they tend to be "Indigo", with bright auras and the ability to perceive things the rest of us don't. It does makes some sense. Kids like Curtis are open minded and absent many of the preconceived notions of typically developing children. They need explanation as to what is "normal" and might not think anything weird of seeing or hearing a ghost.  Anyway, he's never mentioned seeing a ghost, but this little story happened in 2006, not long before Curtis turned two years old, and it's 100% true.
Laura's grandparents had come up for a weekend visit and Laura and I set up the futon in Curt's room to fit everyone into our 2 bedroom space. We gave her grandparents our room and slept in Curtis room not far from his crib. The first night was normal. We both slept fine and there was nothing out of the ordinary. We had no reason to expect anything out of the ordinary. Night two however was a little different.
Laura and I went to bed around 10:30pm but she has an easier time falling asleep than I do. She fell asleep a few minutes after getting into bed while I lay there listening to the clock in Curt's room. I probably drifted off at about 10:45.
At about 11:30pm, Laura and I both shot up out of a sound sleep with me yelling "WHOA!" and her saying "Oh my god, what was that!". I knew immediately she heard exactly what I just heard and also that she would not want me to confirm it, but of course I had too. I couldn't wait too. The conversation went something like this.

Greg: "You just heard that too, right?"
Laura: "What did you hear, no wait, don't say it"

There would be no denying it if we both heard the same thing

Greg: " A woman's voice just said, "What are they doing in here?"
Laura: "Oh my God, shut up"  (pulls cover over her head briefly)

We had both heard the same exact thing

I can't express enough how clear this voice was. It wasn't angry, it wasn't upset, it  just sounded curious. We were both asleep and it was so clear we both looked right above Curt's crib and to the right when we shot up where someone should have been standing. Looking at the same spot and confirming we'd heard the same sentence. It took a long time for Laura to get back to sleep as we discussed what we'd heard. I was pretty sure I was staying up the rest of the night. I laid there thinking about what it could have been. All windows and doors were closed. I dismissed Laura's grandmother as a sleep talking candidate as she speaks with an accent and this voice had none of that. It was just a woman's voice asking a matter of fact question.
So I laid there for about an hour and a half just looking around the room, waiting to hear something again. As I finally started falling asleep, all of a sudden the smoke alarm in Curtis' room starts blaring. This smoke alarm had never gone off before and never again after, but here it was blaring away to punctuate an already bizarre night. Laura jumped out of bed and started fanning the smoke alarm with her pillow. It added levity to the situation and made me laugh since there was no smoke around. I left the room and Laura's grandmother was in a slight panic in the hall, understandably, woken in the middle of the night by a smoke alarm. She followed me downstairs to confirm nothing was on fire and we returned to our rooms. I never let on that I was basically terrified at this point but that it had nothing to do with a potential fire.
I'm pretty sure I didn't fall back asleep again that night. I just laid there trying to make sense of both events. The conclusions I came to were these. I think the smoke alarm was a playful nod to me from whomever it was we heard. I don't believe we were meant to hear that question, but that whoever it was knew they were overheard and the smoke alarm I believe was intended as a playful acknowledgement. One that I wasn't particularly asking for.  This is just my guess. The other conclusion I came to is that there was nothing malevolent about that voice. It seemed more like a protector or a friend who just didn't understand why we'd choose to sleep in Curtis' room. Like, don't they know I have things covered during the night? The one thing I always wonder is if it was a ghost of some sort, were they posing the question to a sleeping Curtis, or were they asking another ghost? And if it was another ghost, how many of these things are visiting my kid?
I can't say for sure it was a ghost we heard but it was definitely a loud and clear disembodied female voice coming from a specific location in the room so I don't know what else you'd call it. But I do believe whatever it was liked Curtis and meant him no harm. That was the last night Laura's grandparents were staying that weekend so we returned to our room the next night. After that and for months, I would make sure his bedroom door and ours were both open and I would always be listening for anything out of the ordinary during the night. But truth be told I was in no hurry to sleep in that room or hear that voice again. Even if it meant no harm.

Greg, Dad