How to handle terrible twos?

My nephew is about two and a half now and he has been becoming a demon child more and more each day. My brother won't discipline him and his mother isn't around much because she rather hang out with friends and fool around with guys instead of be a responsible adult mother, my mom spoils him rotten and my dad is the only one that attempts to discipline him. If he doesn't get what he wants he scream at the top nn of his lungs and starts kicking and hitting or he'll grab a toy and throw it at people. I've already got kicked a few times and hit by him IN THE STOMACH and I'm six and half months pregnant so I usually raise my voice at him and tell him no and take his toys away. Unfortunately telling him no and taking his toys away don't do anything but piss him off even more. He threw one of his toy tractors at my mom and it broke in her all because he got pissed my dad said no to him and my mom didn't defend him. We've tried time out and spanking his butt and that still doesn't work it just makes him worse. I don't know what to do and neither do my parents. My brother won't do anything and neither will his baby momma. I'm due in June and don't want my nephew hurting my daughter but with how he's becoming and how angry he gets if his grandma is playing with another baby it wouldn't surprise me if he was to try and hurt my little girl. I'm honestly terrified. He used to be such a sweet little boy but now he's not. These terrible twos are most like terrorist twos. What can we do?