Are you claiming that for essentially anyone in, say, Dublin, announcing that they are now an atheist would lead to their family cutting all ties to them?

Or are you just saying that family members would generally declare their deep sadness at the news, and seek to convince them that this is a wrong belief and a mistake?

The first one is what leaving a cult is like (e.g. if you leave Scientology, most family and friends will be forced by the cult to cut ties, even if they personally wouldn't want to; even more extreme cults may physically prevent you from leaving the compound or even hurt you for the attempt). The second one is just the normal human experience of having opinions and a lifestyle that is not accepted by your family; the same happens to many people if choosing a career their family doesn't approve of, or leaves a job their family considers excellent, or dates someone the family doesn't like, and many other scenarios that have nothing to do with religion.