My uk visa was denied

You’ve been refused under A57 https://www.gov.uk/guidance/immigration-rules/immigration-rules-part-3-students with a number of points raised as to why you do not qualify. The ECO does not believe you’re a genuine short term study applicant who will not work illegally and/or overstay. If you want to reapply you’ll need to look at each point and the evidence you provided and address the deficiencies. In particular you need to provide evidence of the source of your funds and those of your sponsor. Refer to https://www.gov.uk/study-visit-visa/documents-you-must-provide for guidance

To answer some of your specific questions regarding documentation:

Q3. If your brother is sponsoring you, provide evidence of the relationship. Eg birth certificates

Q4. Origin of funds (yours and your sponsor’s) - provide bank statements and evidence of where the money came from. Eg pay slips, income tax returns. See UK Visa Refusal: Provenance of funds/parking and Should I submit bank statements when applying for a UK Visa? What do they say about me?

In a related question My uk visa was refused you’ve asked if you should state you are a student. In your first application you said you were unemployed. It’s not a good idea to change information given in an application that was refused when applying again without explaining. If you recently finished your studies and can prove that, then you could say that you are a student who is continuing their education by studying English. If you’ve been employed but don’t now have a job, then your status is unemployed.

Finally some advice - you’re asking a lot of questions that show you do not understand how to compile a solid, credible application. Do not reapply until you have researched and fully understood the requirements and can provide strong supporting evidence.