Answer to Riddle One: A mirror!

Answer to Riddle Two: Fire!

Answer to Riddle Three: If you ask the brothers “What would your brother say is the right path?”, you will find out the answer. See, if you ask the brother who always lies, he’ll say that his brother would say the path that leads to getting lost. But if you ask the brother who always tells the truth, he knows his brother lies and would tell you to go down the path to getting lost. Either way, you’ve found out which path not to go on!