Some (but not all) exmuslims have issues with their family, most of these arising from Islamic practices so the issue is Islamic in that case not the family. Those particular issues would not arise if it wasn't for Islamic texts. Some exmuslims get on very well with their families even after telling them they have apostatised. Many Muslims also have fallen out with their families over a range of issues and no longer speak to their family but still remain Muslim.
you are absolutely right in much of your words dear Kubra ..but to understand your words clearly.. one has to define..
1). Who is Muslim and who is NOT
2). What kind of Muslims were they( the guys you are mentioning) before and what kind of Muslim are now?
3), in the category of Many Muslims also have fallen out with their families over a range of issues and no longer speak to their family but still remain Muslim.
.. ISLAM or THEIR ISLAM/FAITH may be very little to do with falling out with their families over issues that are not related faith and no longer speak... So that is NOTHING TO DO WITH .. you will find such folks in every faith or in even in the folks with Atheist mindset