ANSWER:

One can’t go around policing people and telling them to do this and not do that. This is not possible. However, one must do his level best in advising others and giving the best example by his own conduct. 

He was on his way in his uncles car when he spotted a Muslim with moustaches.How should he tell him this is wrong etc.What should he have done in such a situation.He also sees many Muslims like these in THE streets when he goes to malls,school etc.What SHOULD he have done,and note he his with his family and SOMETIMES strangers like his teacher.