I'm going to tell my brother to get up
What happened? Why does your brother need to get up?
I am taking care of him for months and he keeps on waking up late.
It's noble of you to take care of your brother, and I hope that you continue doing so if he still needs to be taken care of. But if he doesn't need to wake up early, or if he was very tired the day before, then I think that you should let him sleep and get the rest that he needed specially especially if he's in the age that he still developing growing up.
I'm the big brother and he shouldn't ask why he needs to wake up early. I'm going to hurt him.
In that case, I think you're being abusive towards your brother and I do not recommend you hurt him if he still needs to continue his sleep. You won't like it if people wake you up constantly if you feel very tired, would you?