啡 is only used in the word 咖啡 (coffee). Like 咖, it has no independent meaning - the 口 radical marks it as a phonetic character. Together, 咖啡 is a sound-based transliteration of the English word 'coffee.'
Left mouth radical - the indexing radical. Marks 啡 as a sound-transcription character: the 口 signals 'this character represents a syllable in a borrowed word.' Created specifically for the transcription 咖啡 'coffee,' pairing with 咖 on the left.
Right 非 supplies the sound fēi (an exact match), chosen purely for the syllable to render the second half of 咖啡 (coffee). The same phonetic appears in 排 (arrange), 悲 (sad) and 辈 (generation). The 'wrong/not' meaning of 非 plays no role here.
