Would ne cede apathia sed humanitate be a sensical translation of "give in not to apathy, but humanity"? I am trying to keep this as few words as possible but without sounding too abrupt. I was also modeling this somewhat off of:
tu ne cede malis, sed contra audentior ito
-- Virgil, Aeneid, 6, 95:
you should not give in to evils, but proceed ever more boldly against them
-- Translation from this list of latin phrases on Wikipedia.