Please tell me the meaning of "keep it together".
Answer from a Native speaker
To "keep it together" means to maintain your composure during tough situations. It is a way of saying that you should avoid an overly emotional reaction or suppress some urge or instinct in yourself. In this case, he is saying that as the older brother it is his responsibility to not show his worries or panic. Ex: I have to keep it together, no matter how stressed out I am. Ex: Even though she was really angry, she kept it together.