If I pay a monthly salary to my younger brother to help me in the research of daily intraday cash and F&O trades, can I deduct it as a business expense while filling the ITR?
Any expense that is directly connected to your business can be claimed as a valid business expense in the Income Tax Return. You can thus claim the monthly salary paid as a business expense. However, you must have a clear justification and valid proofs to explain it to the Income Tax Officer.
Further, if you pay the salary directly into the bank account, the bank entry is itself a valid proof. However, you must deduct TDS if required and issue Form 16.