My brother tells me that I often sit up and talk while sleeping.

But the weird thing is that sometimes my brother has conversations with me while I'm sleeping. It's just small things but still it's really weird. Like he said this happened:

I sit up.
Me: <Brother>! <Brother>! Do you think I can go on the computer?
Brother: No. I think you're asleep
Me: Oh. Okay.
Then he said I fell back down.

I just think it's weird but also do I actually process information while sleeping?? My brother thinks that I would have done that even if he weren't there, but how did I respond to him??