Is it permissible for a man to transfer ownership of his property to his daughters through a sale, out of fear that their rights might be lost, given that he has a brother and a sister, as well as children of a deceased brother, and a son of a deceased sister?

A man gifting his property to his wife and daughters can take three forms:

The first form: He gifts or sells through a preferential sale while in good health. This is permissible, and the properties become theirs if they take possession of them and dispose of them. The gift or sale is not invalidated even if the intent is to disinherit some heirs, though this intention is sinful.

The second form: He does so while in good health, but the gift is not taken possession of until his life-threatening illness. In this case, the gift is invalid and takes the ruling of a bequest to an heir, which is not executed unless the remaining heirs consent.

The third form: He does so during a life-threatening illness or writes it for them to take effect after his death. This is similar to the previous case.

In the event that the daughters and wife spent from their private funds on building properties: if this was in the form of a gift, then the properties belong solely to the man. If it was with the intention of partnership, then they are partners, and this must be officially documented.