What is the ruling on a father marrying off one of his sons and building a house for him at his own expense, or funding one of his children's university studies? Is he obligated to give the rest of his children the same, or are they required to repay him later?

The preferential treatment of some children over others in giving gifts is a matter of disagreement among scholars. The chosen view is that equality is obligatory unless there is a legitimate religious reason, such as a child's need due to poverty, illness, pursuit of knowledge, or need for housing. If equality is impossible, the one in greater need is prioritized. The father is not legally obligated to pay university expenses. As for a father marrying off his poor son, the majority of scholars believe it is not obligatory for him, contrary to the Hanbalis who consider it obligatory if the son's maintenance is on his father. If a father marries off his son, he has the right to reclaim what he spent, and similarly for university study expenses. As for a father selling a part of his land to marry off one of his sons without the others, this is a preferential treatment that is not permissible except with a legitimate reason.