Sir, my elder son (18yrs). is having a mentality of the fact that He is the best and all other in his known circle are either corrept, shameless, poor,doesnt know nothing , etc etc If any debate occurs he has the fitting that he knows every thing about the topics and other dosent. What to do
Degree understand your concerns went through your details. I suggest you not to worry much.  Don't worry about his attitude for the time being. He is 18 and naturally have high self-esteem. He is behaving like this because he wants to be a positive thinker and wants to keep his attitude positive. Leave him like this. If you try to advice him now, that may have adverse effects. People always learn from their experiences. He shall also learn from his experiences. He shall undergo natural experiences which should bring down his ego and esteem down. Your role as a parent and mentor should be positive then. You should be able to motivate him then. Be prepared, the time shall come anytime now. If you require more of my help in this aspect, Please post a direct question to me in this website. Make sure that you include every minute details possible. I shall prescribe some psychotherapy techniques which should help you cure your condition further. Hope this answers your query. Available for further clarifications. Good luck.