Question

わたしの　そふは　ちちの　あにです。translate

Answer 1

"My grandfather is my father's older brother."

Literally: わたしの (my) そふ (grandfather) は ... ちちの (my father's) あに (older brother) です (is).

Note: biologically this is unusual (a grandfather is normally a parent's father). If you meant "my grandfather is my father's father," say: わたしの祖父は父の父です。