what are the suppossed roles of international organizations and laws nowadays?

Answer 1

There are hundreds of major international organizations. They all have different roles. You need to be more specific. Generally, they either coordinate between states, enable some states to aid others, or enforce international treaties.

Answer 2

International law is a nice idea, but honestly not fair, since only the people of selected countries should choose which international laws they uphold. Also countries only follow "international law" when they are compelled to when it goes against their interests. So what are the roles? A general framework and a set of guidelines as opposed to hard state sanctioned laws.