What is the share of each heir from my deceased brother's estate, and does the house he built on his mother's land enter into the inheritance by valuing the building only, without the land, knowing that my mother and siblings do not agree to that?

If it is not proven by clear evidence or legal documents that the mother gifted her son the land on which he built his house, then it is considered a loan (ariyah), and after the termination of the loan, the son is entitled to the value of his construction as dismantled. The mother's estate is divided as follows: The wife gets one-fourth due to the absence of a direct heir. The mother gets one-sixth due to the presence of a group of siblings. The remainder of the wealth is divided among the brothers and sisters, with the male receiving two shares and the female one share, provided they are full siblings or maternal siblings. The matter of estates must be referred to the Sharia courts to verify all aspects related to them.