But what do I do now? Any tips? Anybody in a similar situation as me? How can I protect myself from manipulation or at least be aware of it? What point do I know I need to cut him from my life?

I commented on your previous post, and I had a somewhat similar situation growing up minus the financial part.

The only thing that worked with my abusive parents was to completely cut them out of my life for about 2 years. They kept messing with me and I gave them a final warning - keep doing this and you won't know my address. You won't know my phone number. If we have any contact it will be completely on my terms.

They pushed it and I pulled the trigger.

If I were in your position I would do the following: Dad is out. No money and no contact. He's a grown able-bodied guy who can earn his own fucking money. He's poor because he chooses to be poor. He feels like he has the right to beat you whenever he wants and he can go fuck himself. When he's ready to acknowledge that you're an adult and don't owe him anything maybe we can start having conversations about patching up the relationship.

I'd offer your brother a place to stay with the understanding that this is a "launching pad" to his own independence, i.e. find a job, build some savings, find your own place within a year. He has to understand that if you pull back, all of those expectations will be put on his shoulders as the next sucker in line.

Don't let your dad sucker you in or guilt you.

he then asked 'do you still want to be my daughter?' 'do you still want to be part of the family?'

"I will always be your daughter and part of this family and nothing you can say or do will change that. Engage in whatever control fantasy you'd like, but nothing will change the biological reality of that. I may not respect you, or endorse your behaviors, but I'm still a decent enough human to acknowledge that you're my father and that means something. I can can also love you as my father without being willing to tolerate or endorse your abuse and manipulative behavior.