YOU SAID:
My sister's boyfriend listens to Old Town Road just for fun.
INTO JAPANESE
私の姉の彼氏はただの楽しみのためにOld Town Roadを聞いています。
BACK INTO ENGLISH
My sister's boyfriend is listening to Old Town Road for just fun.
INTO JAPANESE
私の妹の彼氏はOld Town Roadを楽しんでいます。
BACK INTO ENGLISH
My sister's boyfriend is enjoying Old Town Road.
INTO JAPANESE
姉の彼氏はOld Town Roadを楽しんでいます。
BACK INTO ENGLISH
My sister's boyfriend is enjoying Old Town Road.
That didn't even make that much sense in English.