Weird dream!!

Kandy • 43 year old TTC... Keeping the Faith!
So the other night I had a dream that my husband came home from work. when I greeted him by door this elderly lady was with him - she came in, so I'm like "ok who's this?" And my husband said "who's who?" I said "Really?" "The lady next to you dummy! How you bringing people to the house and you don't tell me" - he said "baby there's nobody there" I said "she is standing next to you, I can see her and I'm not crazy" and I continue to say "OK Since you claim you don't see her, then I want her out my home" So I yell at her and said "leave my home you are not welcome in my home!!" The elderly lady kept looking at my husband with very sad eyes and as if shes waiting for my husband to defend her. I said to her "don't look at him, I want you out my house"!!! Then it went dark and I woke up! 
So in the morning I told my husband about the dream and he said "how did she look" I said she's about 70ish, short and very long silver hair" - my husband face went blank - he said one second, called his aunt and asked her if she has a picture of his grandmother - when she text him the pic! I kid you not!! It was the same lady in my dream! I have never met her in my life or seen a picture of her!! She passed 15 years ago!!! 
How is it possible that I dream with someone I've never met and that person happen to be a member in my husband family?? 
I'm still trying to wrap my head around all this!! 
Any thoughts!