Upvote:14
The first two paragraphs of the refusal notice cover the key point: UK immigration does not consider that a short period of unemployment necessarily implies financial dependence. There is a world of difference between that and your brother just helping out.
For that reason alone another application in the near future is unlikely to be successful.
There is no indication here of how long a period of unemployment would be required. Indeed, no such guideline may exist: your circumstances will be considered as a whole, which brings us to the third paragraph.
You have failed to document your financial circumstances in sufficent detail. The officer expects to see a detailed breakdown of your financial commitments including, but not limited to, rent or mortgage payments, other debt repayments, regular expenditure on everyday needs (groceries, clothes, etc.) and any other commitments, along with details of any other income you might have. Without this he cannot fully assess the degree of dependence and another application is likely to fail without it.
Lastly, the document showing your relationship with your brother is not accepted by UK immigration. You should include both your birth certificates in a future application.