✅ Answer: Please study the following narrations carefully:

ابی بصِير عَنْ ابی عَبْداللَّهِ قَالَ قُلْتُ لَهُ الرَّجُل لَهُ الْوَلَدُ يَسَعُهُ أَنْ يَجْعَلَ مَالَهُ لِقَرَابَتِهِ فقال هُو مَالُهُ يَصْنَعُ بِهِ مَا شَاءَ إِلَى أَنْ يَأْتِيَهُ الْمَوْت إِنَّ لِصَاحِب الْمَال أَنْ يَعْمَلَ بِمَالِهِ ما شَاءَ ما دَامَ حَيّاً إِنْ شَاءَ وَهَبَهُ و إِنْ شَاءَ تَصَدَّقَ بِهِ و إِنْ شَاءَ تَرَكَهُ إِلَى أَنْ يَأْتِيَهُ الْمَوْتُ فَإِنْ أَوْصَى بِهِ فَلَيس لَهُ إِلَّا الثُّلُثُ إِلَّا أَنَّ الْفَضْل فِي أَنْ لَا يُضَيِّعَ مَنْ يَعُولُهُ وَ لَا يُضِرَّ بِوَرَثَتِه

📚 Tahdhib vol.9 p.188

Abu Basir said: I said to Imam Sadiq (peace be upon him): A man has children, is he allowed to give his property to his relatives? The Imam said: It is his property, and until his death comes, he can do whatever he wants with it. Indeed, the owner of the property has the right to do whatever he wishes with his property as long as he is alive: if he wants, he gives it as a gift, if he wants, he gives it as charity, and if he wants, he leaves it until his death comes. Then if he (wants to) make a will with his property, he is not entitled to more than one-third of it, unless it is better and more virtuous not to abandon his family and not to harm his heirs.

عَنْ أَبِي عَبْداللَّهِ فِي الرَّجُلِ يُعْطِي الشَّيْ ءَ مِنْ مَالِهِ فِي مَرَضِهِ قال إِنْ أَبَانَ بِهِ فَهُوَ جَائِزٌ وَ إِنْ أَوْصَى بِهِ فَهُوَ مِنَ الثُّلُث

📚 Kafi vol.7 p.8

Imam Sadiq (peace be upon him) said about a person who gives something from his property to someone during his illness: If he separates it and hands it over to that person, it is permissible, and if he makes a will for it, it is part of the 'thuluth' (one-third).

✅ Meaning, it is considered among the one-third of the property about which a person has the right to make a will, and the rulings of the 'thuluth' property apply to it.

عَنْ أَبِي عَبْداللَّهِ قَالَ: النُّحْلُ وَ الْهِبَةُ مَا لَمْ تُقْبَضْ حَتَّى يَمُوتَ صَاحِبُهَا قَالَ هِيَ بِمَنْزِلَةِ الْمِيرَاثِ

📚 Tahdhib vol.9 p.155

Imam Sadiq said: A 'nihlah' (gift) or a 'hiba' (gift) that has not been received until its owner (i.e., the giver) dies, is considered an inheritance.

أَبِي عَبْداللَّه قَالَ: الْهِبَةُ لا تَكُون أَبَداً هِبَةً حَتَّى يَقْبِضَهَا و الصَّدَقَةُ جَائِزَةٌ عَلَيْه

📚 Tahdhib vol.9 p.159

Imam Sadiq said: A 'hiba' is never considered a 'hiba' until it is seized and received (by the recipient) and charity is permissible for him.

سَمَاعَة قَالَ: سَأَلْتُهُ عَن رَجُل أَعْطَى أُمَّهُ عَطِيَّةً فَمَاتَتْ و قدْ كَانَتْ قَبَضَتِ الَّذِي أَعْطَاهَا و بَانَتْ بِه قال هُوَ وَ الْوَرَثَةُ فِيهَا سَوَاءٌ

📚 Kafi vol.7 p.32

Sama'ah said: I asked (Imam Sadiq) about a person who gives a gift to his mother and dies while she has received what he gave her and separated it; the Imam said: That man and the rest of the heirs are equal regarding that thing.

✅ Meaning, because that man was the giver of this thing to his mother, it does not belong exclusively to him, and that gift is part of the inheritance, and all heirs are partners in it.

✅ According to the above narrations, a person has the right to give and donate any amount of his property to anyone he wants during his lifetime and give it as charity, but if it is not separated from his property and is not received by that person until the giver dies, it is not considered a gift, and what he apparently and verbally gifted is considered an inheritance after his death and has the rulings of inheritance. And if he makes a will for that thing to be given to someone after his death, it is considered part of the 'thuluth' of the property and has the rulings of the 'thuluth' of the property.

✅ In the case of the question, since the giver merely changes the deed to the name and does not separate it and hand it over to his sister and postpones it until after his death and in fact makes a will that this house should be given to my sister and her children after my death, this act has the ruling of a will and the rulings of the 'thuluth' of the property. And according to the narrations, as long as this house does not exceed the 'thuluth' of his property, it will be given to his sister as a will of the 'thuluth' of the property. But if he does not make a will and simply gifts the house to his sister but does not separate it and hand it over to her so that his sister can do whatever she wants with the house, with the arrival of this person's death, the gift is nullified, and that house is part of the inheritance that will be divided among the heirs. So this person, if he does not separate the house and hand it over, must make a will for it as part of the 'thuluth' in his will so that it reaches his sister.