Say they thought they were getting the house split 3 ways - it's a big 2 story over basement house, worth maybe €1.5million? Maybe more? Children can inherit €335,000 from a parent tax free so if they were getting €500k each out of the house they would have 33% CAT on the balance, so a tax bill of around €50k each so that leaves each son getting about
€450,000.You could buy a regular house in Dublin for that, or have a tiny mortgage. But then Mum who left them when they were children swoops back in and literally pulls the rug from under them.
What I would wonder is, whether the mews house is listed separately from the main house. Because if the MiL sells up, they could be left with nothing.