YOU SAID:
My dad went to get the milk but hasn't returned yet.
INTO JAPANESE
父はミルクを取りに行きましたが、まだ戻っていません。
BACK INTO ENGLISH
My dad went to get some milk, but he hasn't returned yet.
INTO JAPANESE
父はミルクを飲みに行きましたが、まだ戻っていません。
BACK INTO ENGLISH
My dad went to drink milk, but he hasn't returned yet.
INTO JAPANESE
父はミルクを飲みに行きましたが、まだ戻っていません。
BACK INTO ENGLISH
My dad went to drink milk, but he hasn't returned yet.
That didn't even make that much sense in English.