YOU SAID:
Coffee is his perfect.
INTO JAPANESE
コーヒーは、彼の完璧です。
BACK INTO ENGLISH
Coffee is perfect for him.
INTO JAPANESE
コーヒーは彼のために最適です。
BACK INTO ENGLISH
Coffee is the best for him.
INTO JAPANESE
コーヒーは彼のために最善です。
BACK INTO ENGLISH
Coffee is the best for him.
That didn't even make that much sense in English.