Estius: some acts of pagans are not sins but imperfectly good
Estius takes this view on the second book of the Sentences, distinction 41, paragraph 3. He asserts there that some actions of unbelievers are not only not sins but are morally good, though imperfectly. He notes that by 'unbeliever' he does not mean a Jew or a heretic, even though such a person in truth has no faith, since faith is the name of a whole virtue. He means a pagan or heathen, who has no knowledge even of the one God to whom he might refer his actions.
He thinks such an unbeliever sometimes acts from a natural affection that of itself tends toward good, and directs some actions not to a bad end but to the good and to the last end, known in general and vaguely. In his judgement that is enough for them not to have the character of sin.
The righteous in this life do not refer all their actions to God, whom they hold as their last end; they do not so refer those in which they stumble daily. Likewise, he thinks, the unrighteous, even unbelievers, need not refer all their actions to what their corrupt will has set up as the thing to love above all.
Just as desire sometimes slips into the righteous some movements of the will that are not referred to God as last end, and cannot even be, so, on his view, the natural instinct for good sometimes draws from unbelievers actions that a man does not refer to what he loves in particular as the highest good. He refers them to the good and to the last end, at least in general, though he does not know what that end is in particular and distinctly.
Latin
XXVIII. Quam sententiam amplectitur Estius in secundum sententiarum Distinctione quadragesima prima paragrapho tertio. Ibi enim asserit quasdam infidelium actiones non tantum non esse peccata, sed & moraliter, licet imperfecte, bonas. Et notat hoc in loco a se infidelem non dici Judaeum aut haereticum, tametsi revera talis fidem non habeat, propterea quod fides integrae virtutis sit nomen, sed paganum, seu Ethnicum, qui ne unius quidem Dei, in quem suas actiones referre possit, cognitionem habeat. Censet enim ejusmodi infidelem aliquando operari ex naturali affectu, qui ex se ad bonum tendit, & actiones quasdam non in malum finem dirigere, sed ad bonum & finem ultimum in genere & confuse cognitum; quod sufficit ejus judicio ut non habeant rationem peccati. Nam sicut justi in hac vita non omnes suas actiones in Deum, quem habent pro fine ultimo, referunt, eas nimirum in quibus quotidie offendunt: ita nec necesse putat, ut injusti, licet infideles, referant omnes suas actiones, in illud quod prava voluntate statuerunt sibi summe diligendum. Quemadmodum enim concupiscentia interdum in justis surripit aliquos motus voluntatis, qui non referuntur in Deum, ut finem ultimum, ac ne referri quidem possunt; sic naturalis ad bonum instinctus aliquando, ex ejus mente, in infidelibus elicit actiones quasdam, quas homo non refert ad illud quod in particulari pro summo bono diligit, sed ad bonum & finem ultimum, saltem in genere, licet quis sit ille finis in particulari & distincte ignoretur.