Also, to those wondering about the door being locked and unlocked.... it was locked because her mom wanted to record that last voice-mail for her daughter. This is why her daughter heard her mom singing to herself very faintly. It was her leaving the voice-mail before she passed. This is my thought atleast

I want to say that your mom is telling you that the man is not bad like she had originally thought. That death is not as scary as we may perceive it to be. She may be telling you that she is in a better place now and to not fear because when it is your time, you will also meet with him and he will take you to be with your family. I would take it as a good message, that you are a good person and have a bright afterlife awaiting you.