Toothpaste

A few nights ago, my brother had another one of his sleep walking things. He got up, went to the bathroom, left the bathroom, then turned around and walked back in. I wondered what he was doing, so I got up and went to the bathroom door which was wide open. Nathan looked right at me and said "I have toothpaste on my hand." He did.
"Why do you have toothpaste on your hand?" I asked.
"I don't know."
I looked at the sink and his tooth brush had more tooth paste on it than brush. "What are you doing?"
"I don't know."
"Nathan, there's Kleenex on the toilet rim, what are you doing?"
"oops." He flushes the Kleenex when there's a trash can right next to his foot. "I don't know."
"Turn off the light when your done."
"Ok."
"Nathan, if you don't remember this in the morning, I'm going to kill you."
"Ha, ha."
He brushes his teeth does NOT turn off the light and crawls back into bed. Why me?

btw, he did not remember it in the morning. typical. don't worry, I didn't kill him.