Does a paternal cousin inherit from his deceased paternal female cousin who has no children, knowing that she has full sisters? And is he entitled to claim the house that was built through the joint effort of the sisters and registered in the names of only two of them?

If the aunt passed away leaving three sisters and a paternal male cousin, and she had no other heirs, the inheritance is divided as follows: The sisters receive two-thirds, as Allah Almighty says: (And if there are two [sisters], they receive two-thirds of what he left). The paternal male cousin receives the remainder by way of 'asaba (agnatic relationship), which is one-third, for the Prophet, peace be upon him, said: (Give the prescribed shares to those who are entitled to them, and whatever remains is for the closest male relative). So the paternal male cousin takes one-third of the entire inheritance.

However, if the four sisters participated in building the house, but it was registered in the name of only two, including the deceased, then the reason for the registration must be known. If the two sisters donated what they paid to their other two sisters, then the house becomes the property of your mother and your deceased aunt. In this case, her paternal male cousin inherits one-third of her share, considering also the ownership of the house's land. But if it was not a donation, then the paternal male cousin must be convinced of this, otherwise the matter should be referred to the Sharia (definition) court.