Is it permissible for a man who was suckled by his paternal grandmother along with his paternal aunt to marry his paternal aunt's daughter or his paternal uncle's daughter, and is it permissible for his brother, who was not suckled by their paternal grandmother, to marry his paternal aunt's daughter or his paternal uncle's daughter?

Fostering establishes the same prohibitions (regarding marriage) as lineage. If someone was suckled by his grandmother along with his paternal aunt, then he is not permitted to marry his paternal aunt's daughter or his paternal uncle's daughter, if his father was the source of the grandmother's milk. This prohibition is specific to the suckled individual himself, not his brothers and sisters. Consequently, it is permissible for his younger brother—if he was not suckled by his grandmother—to marry his paternal aunt's daughter or his paternal uncle's daughter. It is important to note that the fostering which establishes prohibition consists of five full, satisfying sucklings.