Intrigued
Without reading other people's comments, the first thought that entered my head when I read your post is that the "evil" that is invading your psyche is your fear. What are you afraid of? The fact that you dreamed of your family being possessed by this "evil" indicates that your have deep fears about your family. There is something about you, which you fear will affect your family negatively in some way. It may also indicate that your family is a soul group and each of you have your special gifts. It reminds of the cartoon family, The Incredibles. Your younger son is probably too young to realize his gift. Maybe the dream is advising you that it's time for you to be more open with your family about your spiritual gifts. Maybe as a family you are supposed to be doing something great. I see the dream as a statement about unity as a group, and figuring out what your group purpose is. Let go of the fear. Be open to allowing the spiritual gifts of your family to flourish.
Anyway, I am just rambling random thoughts. I'm not sure if any of this resonates with you.
Anyway, I am just rambling random thoughts. I'm not sure if any of this resonates with you.