Your friend is going through a hard time. There are perhaps some life updates that you are really eager to know. You want the dish, you want the scoop. Or you want to put in your two scents, your advice, your what have you. There is space for input from friends, it is undoubtedly valuable. However, sometimes people just want to hang out. They made this time for you in their life to do something together and perhaps they don't want to discuss in detail what is wrong in their lives but rather take a break from it (with you). So a simple "How are you?" suffices and if you are really concerned you can follow up with a simple "How are things going with ______?". But don't push it and don't force it, causing unneeded strain on their already perhaps taxed heart and mind. They know you are for them and will open up when they desire to.