What should we do about a cousin who practices sorcery and harms us, when we have material evidence of this, but his family is asking us to accept his false oath to stop accusing him?

We advise seeking refuge [with Allah] and protection from sorcerers by consistently performing acts of obedience and remembrance [dhikr]. It is permissible to file a complaint with the Sharia court if one is certain that a man has been harmed by sorcery. It is preferable to accept the reconciliation sought by relatives if no harm is feared from it, because kinsfolk are obligated to avoid the escalation of problems and to strive for reconciliation amongst themselves. Jurists have explicitly stated that it is commendable for the judge to encourage litigants to reconcile, and it becomes obligatory if he fears the escalation of the problem. As for the difficulty in proving sorcery, this is correct, and thus, accusing someone of it without evidence is forbidden.