Trouble controlling my 7 year old brother

Hey everyone! So just had a fight with my brother. This rarely happens because I always allow him to do what he wants (avoiding putting my mind with a child as my parents say). However I think this is wrong. Giving him what he wants spoils him, as it happened.

So we have this google device in our kitchen where we use it for following recipes, checking the weather, hearing some news or even playing some music for the kitchen. So he decided to watch a video on YouTube which was super long. I let him at first but then I saw that this would take forever so I said to him calmly “I really need to use this now, you have been using it for too long.” And he said “no”. I let him for three more minutes and went back to him. He refused again. My parents were there the whole time. I then warned him that I would switch off the device and he didn’t care, so I did. He then said “okay, now I’ll watch it all over again” and that’s where the fight begun. I told him to get the tablet and watch as many videos as he wants and he started having one of those deadly tantrums that pierce your ears and never stop. He then grabbed a plastic, heavy toy and started hitting me. I literally was in pain and stayed there calmly trying to stop him. I didn’t shout, I didn’t try to fight back. I only tried to avoid him and grab the toy from his hands because he was hitting me really hard and I was ready to burst into tears out if the pain I had. I didn’t show I was in pain though so my parents didn’t react and let him hit me. When I went in because I couldn’t handle it no more, I pushed him back and that’s where my parents reacted.

I may be 18 but that little brat needs to respect people around him. My parents at least should have had control over him, but they just give up and let him do whatever he wants. It’s sad when a little boy controls a whole house. I hope I didn’t come out as immature. I’m trying to get into the position of a good parent, and a good parent sets boundaries. My parents instead blamed me and now he has the victory. After that fight, my hand was in super pain, I thought I broke it. I’m really pain tolerant so I got scared that something has happened. I’m still in pain but I’ll guess I’ll wait and see how long this will take before calling a doctor.

So, back to the subject. Are there ways to control such a troublemaker? My parents won’t do it but I am because that little guy will turn out to be a bad boy and that’s not what I want for my brother. His tantrums and reactions on anger are serious, he can injure someone very seriously or even kill someone if he holds something dangerous in his hands. I tried putting him time out, he just won’t. He will push you and go away with what he wants. I don’t know with what way to control him. Please respond if you have any ideas...