Is it permissible to boycott relatives who are outside of Islam, and who do not pray or fast, deal in usury, and do not accept advice? And is it permissible to give them from zakat or sadaqah, or invite them to eat?

Invite them with wisdom and gentleness, remind them of Allah, and use recordings and pamphlets that encourage prayer and fasting and warn against usury. Do not sever ties with them unless it is a means of pressuring them to abandon their transgressions. Otherwise, remain in contact with them, for Allah might guide them through you. It is permissible to feed them and give them money if that is to win over their hearts. As for zakat, do not give it to them as long as they abandon prayer and fasting and violate sacred prohibitions.