What is the ruling on the severance of relations by the husband’s children with the questioner after their father married her mother, and does the hadith “No severed of kin will enter Paradise” apply to them?

What the children are doing by abandoning their father and preventing him from marrying is a major act of disobedience (ʿuquq), and it is among the grave sins. Their abandonment of their brother is forbidden and constitutes cutting off ties of kinship. Their abandonment of you is also forbidden. It is advisable to be patient with their harm, for the one who maintains ties is not the one who merely reciprocates. The husband should remind his brothers of God, the right of their father, and the ties of kinship, and that their objection to their father's marriage is an act of disobedience.