What should I do in the bad times of my brothers?

I want to say that we are seeing how are the current world leaders killing our Muslim brothers for no reason. And the current Muslim leaders are behaving like they are seeing nothing. Some of them for their own interests and some of them fear current world leaders more than ALLAH. Of course they will be punished for both reasons because they didn't help their brothers in danger. Most probably, more difficult time is coming for Muslims. Now as normal Muslim, I want to know what should I do at the bad times of my brothers?