Under the statutory right to Dependent Leave your employee would not normally be entitled to time off from work unless his/her brother was a dependant and then he/she would be entitled to unpaid time off for a reasonable period.
Compassionate leave is very similar and is usually applied in situations where the emergency does not involve a dependant, and then it comes down to assessing whether or not it would be unreasonable to refuse unpaid time off in the circumstances (based on issues such as the effects the situation was having on the employee).
It is hard to imagine that any employer would want to refuse time off for the funeral and most would provide longer if the relatives had a very close relationship. The period of time that the employee should take would again relate to the amount of time required to deal with the immediate emergency and would not extend beyond that.
So for example, it wouldn’t be appropriate to take four weeks off work to provide childcare for nieces and nephews, but it would more likely be reasonable to take a day or two off work to arrange childcare for them.
Some employers go the extra mile and provide paid leave during such situations but that is a matter for the company policy.