It's reckless not to have stability for the kids, what's going to happen when they cannot afford to keep this new place on but the kids are in school. Will they stay in the catchment area for the school or be moving the kids from school to school, disrupting friendships and routine all so they can look the part on Instagram. If they can (barely) afford to pay 5 grand a month in rent for this new house why not buy in somewhere like Maynooth or Celbridge, and commute into town for work. Lots of people live in areas that meet some of their needs, not all, and make do as it means security.