"Any man who gives a lifelong gift to another man, it belongs to him (the recipient) and his descendants. He said: 'I have given it to you and to your descendants so long as any of you are still alive.' So it belongs to the one to whom it was given, and it cannot revert to the first owner, since he has given it as a gift, and as such, it becomes subject to the same ruling as the estate." (Using translation from Nasāʾī 3748)
أَخْبَرَهُ أَنَّ رَسُولَ اللهِ ﷺ قَضَى أَيُّمَا رَجُلٍ أُعْمِرَ عُمْرَى لَهُ وَلِعَقِبِهِ فَقَالَ قَدْ أَعْطَيْتُكَهَا وَعَقِبَكَ مَا بَقِيَ مِنْكُمْ أَحَدٌ فَإِنَّمَا هِيَ قَالَ أَبُو بَكْرٍ لِمَنْ أَعْطَاهَاوَقَالَ عَبْدُ الرَّزَّاقِ لِمَنْ أُعْطِيَهَا وَإِنَّهَا لَا تَرْجِعُ إِلَى صَاحِبِهَا مِنْ أَجْلِ أَنَّهُ أَعْطَاهَا عَطَاءً وَقَعَتْ فِيهِ الْمَوَارِيثُ