What is the ruling of Islamic law regarding the distribution of the inheritance of a man who died leaving a wife, sons of a deceased brother, and sons of a deceased sister, with no children of his own?

If the deceased has no heirs other than those mentioned, his wife receives one-fourth as her prescribed share due to the absence of a lineal descendant, based on the Almighty's saying: ﴿And for them is one-fourth of what you leave if you have no child.﴾ The remainder is inherited by his nephews (his brother's sons) by ta'sib (agnatic inheritance), if they are full-brother's sons or half-brother's sons from the father's side, due to the Prophet's (peace be upon him) saying: «Give the prescribed shares to those entitled to them, and what remains is for the closest male.» As for nieces (brother's daughters), nephews and nieces from the sister's side (both males and females), and nephews from the mother's side (brother's sons from the mother's side), they inherit nothing as they are from dhawu al-arham (relatives through the womb). Inheritances are a serious and complex matter, so a mere fatwa is not sufficient; rather, the matter must be referred to the Sharia courts for investigation, as there might be another heir, or wills, or debts, or other rights that take precedence over the heirs' rights.