My brother said he feels like he has to parent me?

My brother told me this today and I had no idea how to respond. He said this because I didn't do my homework and decided to skip first per. and come in late to avoid embarrassment (stupid, and irresponsible I'm aware). And then he proceeded to called me a failure (in a around about way) but also contradicted himself when he said that I could drop out and get my GED. I'm not saying that makes you a failure, But it just doesn't make sense for him to say that. What he doesn't understand is that I'm depressed (and slightly suicidal) and it's hard to get things done. If you've never been depressed you may not understand this but it makes it really hard to focus and get things done for some. My dad condoned my decision to come in after first period, which made my brother say that my dad was irresponsible. My dad doesn't really understand that he has to put his foot down to make me do things because, being the younger sibling I was never told how to do things, I just had them done for me. Yet I still take FULL responsibility for being somewhat helpless. So whenever I have to do something by myself my anxiety goes through the roof and I end up not doing it. I'm a junior in high school and I'm in accelerated English but I'm still in Algebra because I switched school districts and my old district spreads it over two years. Then they threw me into a class that was doing something totally different and I failed. I just feel like a bad sister for making him feel like he has to "parent" me