My younger brother has been staying up until 2 AM. My mother knows about this but doesn't do much. I feel as if I am risking my health by waking up in the middle of the night to yell him to bed. Should I not concern myself with this? He is 13, I'm 16.

I understand your concern for your brother in that he's not getting a decent night sleep and your mother is not caring about him, by disciplining him in making him stick to a bedtime routine so he can function better, making the boundaries clear between parent and child and so gaining respect.

However, you are making yourself ill over this, sit down and have a chat with your mother and brother and if nothing comes of this, or they refuse to talk, then you have no choice but to just make sure you get a decent night sleep and do well in your life, there's no point in you suffering because they don't care to change.

What he does is not your job to police. His mother is aware of what he's doing leave it at that.  Get your beauty sleep and stop worrying about him.

Why are you waking up to yell at him? Is he making noise and that is what is waking you up? If it is, how about asking nicely to be quiet instead of yelling. You know the old saying about flies and honey? Being angry about the situation is what will ruin your health faster than any lack of sleep. Also if it is the noise, ear plugs can do wonders for a good night's sleep, or a white noise machine.

If his grades are slipping, or yours, you might want to add that to the arsenal when you discuss this with your mother.

Is your bed to close to his bedroom wall? Perhaps rearrange your bedroom.