Wow that is pretty similar to what my uncle went though. He visited relatives in part discussing his upcoming devorce when suddenly police at the door saying his wife killed his 2 kids. 20-30 stabs with the first, fewe the second but the second woke up during her sister beeing killed and had to see it before she died. Mother then walks out of the house to the porch of a neighbour and just sat there covered in blood on a stool when the neighbours saw her confronted her and she just said there was an accident until police arrived. 15 years, which counts as lifelong in my country, with additional safety lockup (or whatever its called, basically will never leave prison if everyone involved isn't 100% sure she would never kill again which never happens so she'll die in prison). This is 6 years ago and surprisingly my uncle still lives.