I had a dream about a month ago and I still don't know what it means:
I was watching my baby brother (whom I have not seen in four years) and this large spider kept trying to bite him and take him away from me. So I would just walk away from it. It wouldn't give up, it kept crawling back. So I chased it into a closet and closed the door. When I opened the door to see if it was still there, a bright light came out and attached to the light were a pair of white feathered wings and thin electric tentacles. I closed the door and backed away, waiting. The door opened and a man stepped out accompanied by a small gray imp-like creature in a jester-like attire. The man was tall and thin and had long black hair. He smiled and told me that I couldn't protect my brother. So I hid my brother in a small wooden box and prepared to fight the demon. It was hard to fight the demon because every time I tried to hit him, he would eat my weapons. He could also transform. The first transformation was the spider, the second was the light, the third was the man, the fourth was a golden dragon mask with sharp, needle-like teeth, the fifth was an extremely thin man (you could see his bones through his skin) that looked as though his skin was made of thin gray clay, and every time a piece of clay chipped off it would turn into ash and leave red marks on his body, the last one was the "Fire Breather" I could only see the flames that tore out of his mouth and the long pale scars on his back. As he was breathing fire the imp said, "You must be careful, master has quite the temper (or something like that)" and chuckled. After that I woke up.

Why haven't you seen your brother in four years? Do you have any reason to be worried about him in waking life?

My brother and I have different mothers and his mother thought it would be best for him if my father and I stayed out of his life. I don't think there is anything to worry about in his life, but I am constantly thinking about how I should be there to help and watch him grow up. I feel that I should be able to have the chance at being his older sister and not wonder all the the time if he knows who I am or not.

It sounds like the "demon" could represent all the different things that you imagine could happe to your brother. The extremely thin man makes me think of Death.

That doesn't mean that anything bad will happen to him, just that you worry about him.

Is there a stepfather or similar man in his life? What is he like?