Is it permissible to boycott a relative who deals in usury, sells land to Jews, and offers forbidden food, and is it permissible to greet him with "peace" (salaam)?

Allah has made it obligatory to maintain kinship ties and has forbidden severing them, considering it one of the major sins. Boycotting a Muslim can be either for a worldly reason or a religious reason. If it is for a worldly reason, it is not permissible for more than three days. However, if it is for a religious reason, such as an innovation (bid'ah) or a sin, then boycotting is permissible until the person abandons it, provided that the boycott achieves a benefit and leads to disciplining the boycotted person and deterring them from the transgression. If it does not achieve this, or if it increases corruption, then one should not boycott, but rather pursue other methods such as encouragement and gentle admonition. The ruling on greeting a person of innovation or sin is similar to the ruling on boycotting: one should refrain from greeting if the boycott is effective, otherwise, one should greet them along with offering advice.