Your need to do something to improve their quality of life is not codependency, is love. What they have among them is codependency.

Remember you are not responsible for their choices, and you cannot force them to change them either. Just make sure they are aware that, when they are ready, you are there for them. That is all you can do besides go nuts, so be careful.

Codependencies are that, dependencies, like alcoholism, and you can go crazy trying to make an alcoholic quit, and it will never happen, unless the alcoholic decides it's time. And even then it is a struggle. For your parents and brother to change their behaviors the need has to come from inside themselves. You can loose your mind trying to make them see.

Be there for them, love them, remember it is their choice, and be ready for when they are ready.

gab