Assal?m alaykum.
Beloved Shaykh i would like to know the ruling regarding two sons who're muslims but their mother is a non-muslim (Christian) who is unfortunately mentally ill for years now she has a piece of land under her ownership can her two sons use it or sell it for themselves considering that she's been mentally ill for years since they were young boys they're currently in their 50's,considering that in Islam we are not allowed to inherit from non muslims however in this case she's still alive .

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 is His slave and Messenger.

These two sons do not have the right to dispose of their mother’s land for their personal benefit, whether by sale or otherwise, because the land is her own property and not theirs. The fact that she is a non-Muslim or mentally ill does not, on its own, entitle them to take her land or assume ownership of it and dispose of it. An insane person is not denied ownership of his property merely because of his insanity, and likewise, a non-Muslim is not denied ownership of his property merely because of his disbelief. Also, the fact that they do not inherit from her if she dies does not allow them to seize her wealth in her life. They also have no legal guardianship over their mother’s wealth because the guardianship over wealth is exclusively assigned to the father and grandfather from among the relatives. The author of Asna Al-Mataalib said: “Legal guardianship over wealth is not affirmed except to the father and grandfather.” [End of quote] If their mother were a Muslim, they would have no right to dispose of her wealth for their personal benefit, and since she is a non-Muslim, they have no right to dispose of her wealth with greater reason. In brief, it is impermissible for them to take that land.

Allah Knows best.