In certain countries it is expected that the children will grow up and provide for their parents when the parents have need of support. Unlike the U.S. where children leave the family home then return expecting support from older and often elderly parents, other countries are of the mindset where the child is the support/retirement provider upon old age of the parent.
It is normal for elderly people in Bosnia to live with their sons or daughters. While there may be other options, many people like to stay with their own families. If this is possible, it is ideal. If there is no one able to care for an elderly person, they may be taken care of by the state.