Bad dream with terrifying consequence..

In the Iban culture, when you dream about loose, rotten, or missing teeth, it indicates that a family member or close friend is very sick or even near death. I was horrified when I dream about my tooth falling last few weeks back. I did not want to tell anyone about. However, I told Nana and few others about my dream. Nana told me that she had a similar dream once and soon after that, someone's dad made his way to Heaven.
Coincidentally, three nights before, my brother informed me that his best buddy Doster had just passed away. And I dream about it not too long ago. So, is it true that such a dream do serve as a warning? Hopefully it is JUST a coincident. Otherwise, it would be a daunting warning that we will be losing someone who is dear to us. Just a matter of time.. I want to have such a dream no more!