Something Unusual Is Going On Im My House.

In my house, as the majority of people, I have a computer, and the settings of the screen saver are set to start after 3 minutes of inactivity...
Something unusual happened a few years ago and again last year and last week-end as well.
Almost 5 years ago, my dad passed away and right after, this happened:
It was night and I was sleeping, at that time, I lived in a studio apartment, and my "Mac" was on the opposite side of the wall compared to the bed, more than once, the screen saver stopped working, (like someone just touched the keyboard or moved the mouse) and the room lighted up because of the brightness of the screen, I did not pay any attention to that, more than thinking it was strange.
Now, I lived in another house and the Mac is in the guest room... Last year my mother went to visit me and once she was sleeping while all of the sudden she told me: "The computer just turned on and woke me up!", (she meant the screen saver turned off and the screen lighted up)...
Last week-end, I got married and after the reception, once I arrived home, I noticed that the Mac screen was on, but no-one was home, and I thought: "This is my dad who came and visited me because of this happy event", in any case I checked the settings of the screen saver but everything was normal.
The screen kept being lighted up all night, and I decided to turn off my Mac because the brightness of it came through my room and it was difficult for me to fall back asleep...
After that day, the computer started to act normal as usual...