YOU SAID:
I was coming back from work when i saw him coming back home
INTO JAPANESE
彼が家に帰ってくるのを見たとき、私は仕事から帰ってきた
BACK INTO ENGLISH
I came home from work when I saw him coming home
INTO JAPANESE
彼が帰ってくるのを見たとき、私は仕事から帰ってきました
BACK INTO ENGLISH
I came home from work when I saw him coming home
You should move to Japan!