What is the dividing line between hypocrisy and flattery? Can true friendship be tainted by some hypocrisy? Is the behavior of the aforementioned friend considered hypocrisy? And what is the consequence of friends' hypocrisy?

In summary: Some people confuse hypocrisy (nifaq) with mollification (mudara) and compromising one's principles (mudahana). Hypocrisy (nifaq) is displaying good outwardly to inflict evil. As for mollification (mudara), it is showing friendliness to deal with ill-mannered individuals or to ward off their harm without assenting to their falsehood. This is a praiseworthy quality of believers. As for compromising one's principles (mudahana), it is showing approval of a transgressor's sin without denouncing it, and this is forbidden. In friendships, affection should be rationalized and not exaggerated, and true brotherhood elevates one above formality and false courtesy.