What is the ruling of Islam on the action of a wife who seized part of her husband's property and half of his pension, claiming that he has dementia, even though the Sharia stipulates that the wealth of a person who has lost his mind should not be taken until after his death, and what are the verses and hadiths related to that?

It is not permissible to dispose of another's property except with their permission. The ruling of interdiction (hajr) against someone who has suffered an affliction does not take effect unless decreed by a ruler or a Sharia judge who appoints a guardian (qayyim) over the interdicted person's property.

The guardian is obligated to preserve the interdicted person's property from damage and to develop it. They are not permitted to dispose of the property except in a way that benefits the interdicted person. They are prohibited from donating or disposing of anything that does not serve the interdicted person's interest.