How is inheritance divided between the wife and the full paternal uncle, knowing that there is a son of a full sister who died before the deceased?

The nephew (sister's son) is not an heir. If a man dies, leaving behind only his wife and his full paternal cousin, then his wife receives one-fourth as a prescribed share due to the absence of any lineal descendants. The full paternal cousin receives the remainder by way of ta'sib (agnatic inheritance). Thus, the estate is divided into four shares: one share for the wife, and three shares for the full paternal cousin.