I'm so sorry to hear this! I could only imagine the stress that you are going through with having the weight on your shoulders! Family can be some of the most difficult to deal with in your life. I had a little situation come up with my father and he was just going to completely ignore what happened and expect me to just act like it never happened. Finally after two weeks of just silence I finally called him and asked him how could he go on and not say anything? Overall I had to confront him even though he is the older one and the on that caused the problem. It ended up making both of us cry. Overall I just had to gently come out and say something, because if I didn't it would have just weighed on me over time and stressed me out more. In your situation it just seems that everyone else just pushed what happened to the side and you truly care for your little brother and it hurts that no one said anything or even apologized to anyone for anything. My big thing with my father was I was wanting an apology and it made feel like crap that being his daughter had to pretty much call him out and make him. It just me seeing that he didn't care. Overall I just had to call him out, not being angry, just gently saying something to start the conversation.