What is the ruling on holding a wedding celebration at the wife's home with a feast prepared by the wife's family, and is it considered an innovation (bid'ah)? And what should one invited to this feast do? Is it obligatory to accept the invitation? And is it obligatory to denounce the one who does this?

It is permissible to celebrate the wedding at the wife's house and to hold a feast for it, inviting people thereto, so long as Islamic guidelines are observed and reprehensible acts are absent.

The fundamental principle for non-ritualistic actions is permissibility. Some scholars have even deemed non-walimah invitations desirable due to the feeding of people involved.

To argue that these celebrations are bid'ah (innovation) because there is no prophetic command or action to support them is incorrect, as this applies to acts of worship, which are restrictive in nature, not to customs, which are permissible in principle.

Responding to these invitations is desirable according to the preferred view, as it brings joy to the inviter, and due to the agreed-upon Hadith of Al-Baraa: "He commanded us to answer the invitation [of the Muslim]."

If the celebration includes reprehensible acts, then it is obligatory to object and not to answer the invitation unless the objection is made.