Is it permissible to boycott one's siblings who do not visit the questioner, knowing that her husband made her swear not to speak to them unless they initiate the visit or call?

Maintaining kinship ties is one of the important obligations of Islam, and Allah has linked it to His worship, while severing them is among the gravest prohibitions. It is not permissible to abandon brothers even if they abandon you, for the one who maintains ties is he who connects with his kin when they cut him off. The husband must help his wife maintain her kinship ties and expiate his oath if he sees that something else is better than it.