This is one of the most bastardized phrases used by churchians and one of the most egregiously stupid. Every time they use the phrase it’s not for its actual meaning it’s to pretend you must enable sin because people do it. To churchians false kindness and kumbayah singing is “love”, this modern insane definition is the equivalent of helping a junky OD and calling it “love”.
Love is not cruel or kind, love is doing what’s best for someone. If you love someone they might scorn you for it, but that’s the cost of it. Enabling the sinner is not love, it is sin.
People who say that don't understand that enabling itself is just as sinful as the sin being committed in the first place.
You must help your brother out if you can, but helping him doesn't mean just absolving him of his sins outright like a naive fool. Help can be cruel, it can be limited, and it can be cut off entirely. All of these things are better for someone at times than pure dopeish "love."