What is the ruling on using a brother's belongings, such as perfumes and shampoo, without his knowledge, and does sin result from that?

If the brother has not explicitly or implicitly permitted the use of something he owns, it is not permissible for the brother to benefit from it. If something is taken without permission, it must be returned; if that is not possible, then something similar must be returned. There is no harm in returning it without the owner's knowledge if there is a need for that. However, if the brother has given permission, or if it is known that he would be pleased for his brother to benefit from something he owns, then there is no sin in that.