People's dreams can be roughly divided into two categories:
One is to express the meaning behind the events in reality in the subconscious. Note that the "meaning" mentioned here is the accumulated meaning of your own life experience, not popular; Just like the prophetic poems of all countries in the world, they are extremely obscure and need to be analyzed in combination with the reality of the dreamer;
Second, literal translation, just like English translation, the meaning represented by English itself can directly express our meaning;
Your dream, in my experience, should belong to the second kind;
There is no particularly accurate basis for your ill feelings towards your cousin, but you are simply aware of your fear of him, and the subconscious simply uses the analogy of killing with him to explain or foil your distrust of him and the possible risks after following him;
We humans have a sixth sense, which is basically recognized by most people, but the accuracy of the sixth sense is closely related to the richness and understanding of everyone's life experience, which is why some people's sixth sense is often right and some people's sixth sense is often wrong. The sixth sense is the essence extracted after we fully understand life.
So, I suggest you ask yourself seriously, what bad feelings do you have for your cousin? What proven behaviors of your cousin will cause harm to you or others? What is his family's evaluation? Does he have a steady job? What social classes are his friends? Is the main form of his economic income legal income or other ways that are not recognized by law and society?
If you can figure all these out, you should understand what specific aspects of your fear of him are, and then you should avoid them.