The tapping sounds that you heard were either emotion-related hallucinations or they were actual physical noises but without a known cause.
Another but less likely possibility is, maybe it was just a mean prank by someone. Your story reminded of a time when I was small and I was hiding inside a room of my grandparents'. At one point, when my grandparents got into the bed to sleep and the lights were off, I started to make some creepy sounds on the side of a large briefcase that I was sitting behind. I was making tapping and scratching sounds to scare them. And it worked.
All of that aside, I am most sorry to hear about your mother.
Another but less likely possibility is, maybe it was just a mean prank by someone. Your story reminded of a time when I was small and I was hiding inside a room of my grandparents'. At one point, when my grandparents got into the bed to sleep and the lights were off, I started to make some creepy sounds on the side of a large briefcase that I was sitting behind. I was making tapping and scratching sounds to scare them. And it worked.
All of that aside, I am most sorry to hear about your mother.
