What is the share of the father, mother, full siblings, and the children of the deceased full brother from the estate of a man who died?

All that the deceased left behind is divided between his father and mother. The mother receives one-sixth due to the presence of siblings, and the remainder goes to the father. The siblings and the sons of the deceased brother receive nothing, as they are excluded by the father. The proof for this is the Almighty's saying: (But if he had no child and his parents inherited him, then for his mother is one third. But if he had brothers [or sisters], then for his mother is a sixth, after any bequest he [may have] made or debt.) [An-Nisa: 11].

This is a case where the siblings are both excluders and excluded; they reduced the mother's share from one-third to one-sixth, and they were excluded by the father because he has a stronger claim to the deceased than they do, according to the Prophet's (peace be upon him) saying: "Give the prescribed shares to those entitled to them, and what remains is for the nearest male."

It is advisable to refer matters of inheritance to the Sharia courts for investigation; there might be another heir, bequests, debts, or other rights that take precedence over the heirs' rights.