It should be noted that accepting feast of a Muslim is among his rights. However, since the current period is of sin, disobedience and being fed up of religious teachings therefore the details regarding attending such ceremonies is that, If prior to attending the ceremony, one is aware that useless activities and singing etc. will be performed then it is not permissible to attend such ceremonies. If he becomes aware after reaching then if he has enough influence, he should try to stop those activities. If he is not able to stop and is not among those who is followed by others then he can stay. But the one who is followed should not stay and try to leave the ceremony