Perhaps in a Binary world where either love or fear exist but not both, apathy would qualify.
Maybe a thinking such as:
Love = 1
Fear = -1
Apathy = 0
Within the domain of uncontrollable feelings, the opposite of love is fear, not apathy.
In the Greek suffix, Fear is PHOBIA and Love is PHILIA. Both are uncontrollable feelings for or against an object.
Granted this interpretation is in regards to a brotherly love, vice AGAPE or sacrificial love.
It’s interesting to note that the 3 time Christ queried Peter if he loved Him, the first two times Jesus Christ asked if Peter AGAPE’d Christ, and Peter responded he PHILEO’d Christ and the third time, Christ asked if he PHILEO’d Christ.
I would respectfully disagree. One can love someone they fear. We are to love God and fear him. One cannot love and be indifferent towards someone.