Are the apartments that a father designated for his children considered a gift, knowing that they were not officially registered, and should a similar apartment be designated for the deceased brother?

Scholars have stipulated that preferring some children over others for a specific need is not among the prohibited forms of favoritism. Examples include a child who is in need, ill, has a large family, or is engaged in seeking knowledge, or if the other child is disobedient (fasiq). This gift should be proportionate to the need. If the need is solely for housing, then mere usufruct is sufficient without transferring ownership. Since the father passed away before the adjustment, the gift is considered binding by most scholars, while some hold it to be invalid. Shaykh al-Islam Ibn Taymiyyah indicated that the child who was favored should, after the father's death, act justly among their siblings. The lack of official documentation does not matter as long as possession has taken place.