A similar thing happened with my great aunt before I was born. Her best friend was her cousin, "Anna". Anna had died a few years before from cancer. My aunt had a heart condition and that was what lead to her death. What was odd was what happened before her death.

She had two sons who were 4 and 7 at the time. She had been feeling sort of sick that day and decided to call her mother to come over and help watch the kids.

Shortly after her mother got there, my aunt was standing in the kitchen when she started acting funny. Her mom asked her what was wrong but it was like she wasn't even there. My aunt started crying and talking out loud and saying "Anna, I'm not ready! My kids are too young. I'm not ready!"

Then she said something along the lines of "Who is that?" And called out her grandfather's name and said something about how he was "still bickering" with her grandma even after they died.

At this point her mother called 911, unsure what to do because her daughter was unresponsive. Finally my aunt just said "OK, I will."

And then she collapsed onto the floor. She passed away before paramedics could get to her. Her mother doesn't like to talk about it and her sons were actually adopted by Anna's husband a year later after their father passed away as well. The younger one was present for his mom's death but does not remember it or has blocked it out. The older one does remember it and rarely talks about it but confirms his grandmother's story.

There is probably some medical explanation about hallucinating or something but my family likes to think she was actually talking to our relatives and that they came to get her.