Should you advise your neighbor not to hold his daughter's wedding party with music and dancing, knowing that he owns a café that serves shisha, and you have previously advised him gently?

Enjoining good and forbidding evil is a great and obligatory شعيرة (ritual/practice). You must advise your neighbor with gentleness and kindness, explaining to him the seriousness of forbidden acts in a gentle manner that does not alienate him, such as praising him then advising him. If he responds, then all praise is due to Allah; if he does not respond, then you have fulfilled your duty.