Is a mother sinful for dedicating most of her money—the source of which is farming undivided land, and from the eldest son and maternal uncles—to the youngest son to cover his university and marital needs, to the exclusion of his other siblings?

If a mother favors one of her children in spending due to his need, unlike his siblings, or assists him with marriage expenses to the extent of his need, there is no harm in that. However, if the increase is beyond the known need, it is not permissible. Favoritism is permissible for a specific need or a particular characteristic, such as a large family, engagement in seeking knowledge, or to prevent immorality, and the favoritism must be in accordance with what is customary and good.

As for the money given to the mother by relatives, it is her property to dispose of as she wishes. However, the land inherited from the father must be divided among the legal heirs according to their prescribed shares, and the mother is not permitted to dispose of anything beyond her share except with the consent of all adult, mature heirs.