But parents can change. I have worked with colleagues who managed a project so parents who had children removed delayed having another child until they were able to parent sufficiently (rather than have another baby quickly in an attempt to 'replace' the one that was removed as someone to love and who loves them). And those who didn't have a child until they'd worked with the project for an effective period of time were then able to prove themselves as capable parents. So parents can change. But only with the support and resources our current government has underfunded.
In this case it's desperately sad the mother had no contact with her youngest over Christmas but as yet we don't know if that's because the father refused her calls (it's reported they had a fight and she could have thought he was giving her the silent treatment). Or because she neglected to phone him to check on her youngest.
As yet we don't know why the police didn't follow up the 2 SW requests for safe and well checks. If there were target based crimes taking place in the area the force's priorities might have been on pursuing those (again thank the government for underfunding the police).
It's a desperately sad situation and I hope it spurs people to check on vulnerable children and adults to make sure the likelihood of this happening again is reduced.
A relative of mine was left overnight after a fall but a carer and friend both followed up with family to gain entry to take the relative to hospital. Sad they were on the floor alone for 12 hours but fortunately not 12 days. (There was an emergency cord in the room where they fell but they were so disoriented they didn't pull it).