Is what the father bestowed upon three of his children — free housing for 16 years, in addition to gifting one of them a plot of land — considered just, and what is the ruling of Islamic law on these gifts?

A father's preference for some of his children by providing them free housing while others are not, despite their wealth, goes against justice. Such an act is a sin and an transgression. Mere housing does not make the house their property after the father's death. As for the land that he gifted to one of his sons, it becomes the property of the son to whom it was gifted if the father dies before reclaiming it. This is the opinion of the majority of scholars. If a dispute arises among the children after the father's death, the matter should be referred to the Sharia court for resolution.