Mick, I guess she wants to jump in as a woman and take her mothers place but I suspect there is a problem between her and her father. Nothing to do with your marriage MICK. Did you have an idea of that? These issues must be put aside for the sake of the children. Perhaps he is not perfect, but he still their father. Everyone should be united in the death of their mother, and work together to build a stable family for the children. Perhaps they can live with their new mommy. I am sure that would cause many problems, but ultimately the kids would adjust.
Ask the kids what they want.Don't forget their opinion. After the dust settles, lets hope you get back on track. Keep your hopes up. This will make your marriage stronger with communication about difficult issues.
