All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
Inheritance matters are often complicated issues and should therefore be referred to the Sharīah courts or whatever acts on their behalf. These bodies are responsible for examining, verifying, and investigating all issues related to the estate and its heirs, and for ensuring that everyone receives their rightful share.
Such cases cannot be properly resolved through a translated Fatwa (legal opinion) issued from afar.
However, in general:
If property is transferred to another person as a gift during one’s lifetime but the recipient did not take possession of it, then the gift is invalid.
If the transfer is intended to take effect after death, it is considered a Waṣiyyah (will) in Islamic law. A will made in favor of an heir is not valid unless the other heirs consent to it.
As for a non-heir, a will in their favor is valid only up to one-third of the estate. Anything beyond that requires the approval of the heirs.
Allah knows best.