What’s the point in complaining about something when you’re stuck in the situation and nobody is going to do anything to help anyways?

Yep, this is likely what you're working on in therapy - the sadness and disappointment and maybe even depression that come after complaining and people do not support you or meet your needs. You were placed in a really unfair (ETA: and probably overwhelming and stressful) situation- raising yourself and your brother without people helping you. I'm sending you an electronic hug, Internet stranger.