do you care when there is something wrong with your friends or do you let them be.

It depends upon the situation, but I can generally tell if something is bothering a friend of mine. I may say something like "I can tell you're upset about something, and if it's helpful to talk about it, I'm here." However, if they'd rather that I go to the movies, dinner, talk about anything other than what's bothering them to get their mind off the issue, I am fine with that as well.