He and I have worked so hard to be GOOD co-parents (unlike her)
Does he understand that any communication foments the conflict and feeds the frenzy? He has no connection with her, so can he have a boundary to ignore her? If she pesters him and they're not obligated to an contact such as for shared children, then I suspect he would have every right to file harassment or restraining or something, a lawyer could advise. Would your ex do that?