In my case, i just tell my team i pick last and i will play any roles they need.

When somebody in my team failed i tell them nicely if they don't take the advice kindly then i just leave them be. Let them fail for the rest of the game. No point nagging someone who just won't listen. Just do your job in the match is always how i play. If support then support properly if carry then carry properly etc.

Last but not least, when the game goes full retard just go with it.