Is a father's transferring ownership of his apartment to his children's mother before his death considered a deprivation of his siblings from another mother, and must the heirs return their share of the inheritance?

If the father registered the apartment in the mother's name, and continued to live with her in it until he died, then the gift is not effective and the apartment is considered part of the estate. This is because a gift is not binding until it is taken possession of, and possession of a house is achieved by vacating it and enabling the recipient to dispose of it. This is not realized if the husband continues to live in it with his wife.

The apartment must be included in the estate and divided among all heirs due to the invalidity of the gift.