A few years ago my oldest son and his wife moved next door to my parents. My mother has always been a rather controlling woman. My dad is complacent and accepting of her control. But my son thought that he'd be ok living there since she's always been kind to him. It hasn't worked out, so he'll have to move.
That's not the only problem. About two years ago he and his wife noticed a strange anomaly. I was visiting one evening with my son and daughter-in-law and as I approached their home I hear my mother walking, briskly, through their house. She seemed to be in the kitchen area as I clearly heard the cabinet doors being slammed. Their car wasn't in the drive so I assumed my dad was out of the house.
After I'd visited with my son for a few minutes, I mentioned that Grandma must be in a tizzy as I could hear loud noises coming from her house. They both looked at me, stunned, and said that both she and my dad were gone for the evening. They'd been invited to have dinner with friends and had told my daughter-in-law they'd be home after dark.
I became concerned that someone was in their house and suggested we walk over there just to check it out. My son and his wife were hesitant, so I asked why. As they began to tell me about the odd sounds that came from my parents home, I realized that something was seriously wrong. My son informed me that they'd been hearing things like this for a while and the activity increased when my mom was in a particularly bad mood.
Recently my mother has been giving our family a pretty hard time. It can be brought on by most anything she sees fit to be angry over. Right now it involves her over-spending and the fact that my dad can no longer work outside the home. He's in his late 70's and is unable to continue the work he's always done as it is too physical.
Just a few days ago a neighbor was visiting my son. He joked that my parents must be running a race inside their house, when my son's wife told him there was no one home! The neighbor was concerned, like I had been, that there was someone there who shouldn't be.
There has to be "something" there. It escalates whenever my mother's temper does. Any thoughts or information would be greatly helpful.
I've found incense very helpful in keeping monkey business at bay. You could suggest they burn some in their home to at least stop it from visiting them too.
Unfortunately the key to stopping is your mother. So the best you can all do is protect yourselves.
Take care.