Is a father's refusal to take his adult children to visit their non-Muslim maternal relatives in their country—fearing temptation for them—considered a severance of kinship ties, especially since other means of communication exist, and he fears an escalation of conflict with his wife because of this?

Maintaining kinship ties is an obligation, even if the relative is a polytheist. If it is possible to combine the children's maintenance of kinship ties with protecting them from tribulation, then that is preferable. However, if this is not possible, and it is highly probable that they will be led astray and their faith corrupted upon arriving in those lands, then preserving religion takes precedence over maintaining kinship ties. In such a case, communication should be limited to phone calls and messages. The husband is advised to convince his wife with wisdom and gentleness.