Maybe they have a cure for death, but the queen was one of those people who actually wanted to die rather than live. Maybe she believed that God will save her or didn't see the full vision of living a longer life in good health as opposed to bad. This was all despite the insistence from her family to "take the cure". While watching the funeral, maybe they were thinking, "well what if we brought her back", but doing so would be too public and impossible without arousing suspicion. Her body would rot by the time they were able to secretly get to her, so she was "trapped" by her own decision to die. But I think that maybe it was just weirdly phrased statement by Julia Samuel in regards to the family members grieving.