Is it permissible for a pious Muslim woman to stay with her husband who had quit praying out of laziness?

Quitting prayer is one of the major grave sins that come after disbelieving in Allah, but the wife of such a person isn`t considered divorced, rather, she should exert all her efforts in order to bring him back to the way of Islam. However, if his sin is likely to lure her from the way of Islam, then she had better separate from him by lawful means such as Mokhal`aa(When a wife pays a compensation for her husband in return for divorcing her). Moreover, if she exercises patience, and remains steadfast on her faith, then there is no harm in doing that.

Is it lawful or unlawful to take payment of key money?

Are all the children of a suckling woman considered brothers to the strange child whom their mother had breastfed, or just to the one who had suckled with him?

All the children of the woman who had suckled a strange child are considered his/her brothers and sisters.

Is it permissible for a father to divide his property amongst his children except one under the pretext that he has paid for the latter`s tuition? This is knowing that his other children were given the opportunity to pursue their education but didn`t because they were educationally poor. Moreover, is he allowed to give his other children who have helped him with growing his business?