None of this is your fault what so ever. If the family is split up, that is not your fault. You are not tearing the family apart. Your parents are making terrible choices. You are not over reacting. This is not your fault.

Don't try to convince your friends that you are okay. This situation would not be healthy for a full grown adult, let alone a younger person. Reach out and take help. Get yourself out of this situation. If you can't do it for you, do it for your little brother. You can change both of your lives. It could encourage your parents to get the help they need.

This is not a healthy situation and I get it because I've been there. Please don't be afraid to take care of yourself. You are important and you deserve more.