I don't want to give too much information. 
Basically someone I know is going through depression because of family. 
Just to give a bit of like... context their parents know the situation but don't take it seriously, make uncalled for comments, just dont seem to care and so on.
I know the whole situation but when they tell me stuff, I simply don't know what to say. 
Like if I ask them if they're self-injuring (because I'm worried) will they feel offended or something? Or will they feel like I truly care by asking them? 
What kind of things could I say? What kind of advice can I give them? And how do I let them know I care and am always there for them?