I had a toy poodle named Satin, growing up and approx. 21 years she passed away, we were all heart broken. My parents never did get another pet as they found it too hard once those pets leave us.
About 3 years ago my oldest son was staying at their house for three months while they were in Florida, he would often call me say "Mom I keep seeing a little white dog by the front door, or standing by the brick wall, and I hear it running around the house a night". I then told him about our Satin, as he was too little when she was with us.
After telling other family members they all thought my son and I were crazy, until 2 nights ago when my Mom went to bed about 15 minutes later she could hear sounds like a dog running across the hard wood floor in the living room toward her room. She thought it was my new dog Timbit, (she often watch's Timbit for me). Then she thought it can't be Timbit as he is not here. She then felt a jump on the bed, she stated it was like something small jumped on the bed. She could feel the indentation. She felt around but nothing. She even turned the light on but nothing was there.
She then called My son and told him about her encounter with Satin and he said "Nana I told you there was a dog in your house". What I find odd is after 21 years she is now back with us. I will say as many times as my dog has been there over night or a day at play he has never seemed to sense another dog in or around the house. My Mom also nows sleeps in a different bedroom in the same house and Satin seemed to know where she was.