Question

1.My uncle's son is my mother's 2.My brother's is my mother's Кто это ?

Answer 1

Nephew, son (племянник, сын)

Answer 2

1. My uncle's son is my mother's son.
2. My brother's son is my mother's grandson.

In both cases, the relationship is described as follows:

1. "My uncle's son" refers to your cousin, who is your mother's child.
2. "My brother's son" refers to your nephew, who is also your mother's grandchild.