Sleeping and dreaming with my brother. iin?

We're extremely poor and I share a queen size bed with my little brother, it's the second of us and we have to spoon each other to fit in the bed. Well ever since my brother started puberty he started to sleep in the nude.

I had these crazy dreams about having sex and the next morning I realized my brother and I might have actually done it. But it couldn't have been more than a minute because I didn't really fully wake up. I know for sure it went in and I don't think he knows because he didn't seem awkward the next morning. Is it normal for this to happen when you're sleeping in the same bed?