I've been reading a book on Stoicism, and I have a question.

In this book, I'm currently reading, the author says that if someone you know has passed away, you should not feel sad about it because it's the natural process of life. What do you think about this? <br><br>I don't feel sad for that reason because I don't believe that it is a loss for them, but I still feel a sense of loss because they are no longer here with us. I don't know what to make of that.