Instead of saying brother or sister X, maybe you had a nick name more appropriate for them.
A brother in my congregation, just for fun, used to call me brother bottle (frère bouteille) or sometimes brother poutine.....(frère poutine)
Wonder why?
We had a CO named Charland, and I called him brother Charlatan
charlatan / Sa1latA~ / nom masculin (guérisseur) quack[!], charlatan;
(vendeur) trickster, con man; (prêcheur, politicien) fraud, phon(e)
y[!].