Hey man, no need for apologies or explanation. You did exactly what I would have done if my mother had disowned me, and then proceeded to enforce the shunning via everyone else as well. F*ck 'em!!!!
Hope you told your wanker brother to promptly "Toss off", and that he should seek proper financial aide from the Almighty Org, since they are his and her "Spiritual Family". I mean, after all, "Jehovah provides!!!!" Maybe the Almighty Org and it's Shepherds could find it in their hearts to open up their greedy coffers and actually send some financial aide BACK to the very members who donated and slaved for free for them all those years? Hmmmmm?
Your brother probably had the reality cheque of his life on that phone call. Maybe it'll wake his dumb ass up? Bravo for standing your ground and not letting these toxic assholes weasel any money out of you via some guilt trip.