YOU SAID:

my dad can come back with milk, or not.

INTO JAPANESE

私の父はミルクを持って戻ってくるかどうかはわかりません。

BACK INTO ENGLISH

I don't know if my dad will come back with milk.

INTO JAPANESE

お父さんがミルクを持って戻ってくるかどうかはわかりません。

BACK INTO ENGLISH

I don't know if Dad will come back with milk.

INTO JAPANESE

お父さんがミルクを持って戻ってくるかどうかはわかりません。

BACK INTO ENGLISH

I don't know if Dad will come back with milk.