My new brother

I just managed to get entirely dressed when the door burst open. I recognised this person as Lily's big brother, a picture of whom I had seen as I entered the house. At once he burst into a rant in Chinese, and somehow I managed to understand him. I guessed it was because I had Lily's brain and that the most imprinted knowledge if not all the knowledge was in me somewhere.

"What the fuck are you doing home, bitch? Do you want me to tell Dad? Do you want to get pulled out of that shit school of yours and taken back to the lab?" asked Lily's brother, whose name I remembered to be Raymond.
"I-I.." I stuttered in Chinese, looking for an excuse.
"What, bitch, what?" he shouted, getting in my face. Not sure whether to stand up to the jerk or make an excuse for the safety of my life, I chose the latter.
"I wasn't feeling well..." I cried.

"Hmph. I won't tell Dad," he said.
"R-really?" I asked. I knew whatever the lab was, it sounded bad.
"You know what I want in return," Raymond said. I was confused at first, then I remembered what Lily had said about having sex with Raymond.