I have been tipped off by the brother that the folks are "they're awfully religious" the quote is his words.
In my formative years, I would recall my father being uncommitted, my mother being devoutly catholic, and my brother being nominally catholic.
Ideologically and politically, the folks are Conservative, pro-life, anti-gay, economically rationalist and generally far right.
In my brother's teenage years my brother's mass attendance changed from regular to occasionally, while my mother continued to attend every week. My father rarely attended mass, except once or twice a year but he seemed to be a bit lost and not into it really at all.
My brother is a person who rarely looks at the papers, doesn't make it home in time for the news most days, and is somewhat unaware of civic matters and matters of state. Its unremarkable, as many people are like him, I'm just bringing it up because it relates to my next paragraph.
The significance of the last paragraph is that most people like that would not know what the Exclusive Brethren is. They from what I've read or found out, are characterized by intense secrecy, and actions to break up families or not consort with outsiders including family members who are not religious.
I've considered also there may be a smaller chance they're not brethren, but are Jehovah Witness or Mormon.
In litigation I went through with them, I'd asked if another person/s or organizations was funding their attorneys' and counsel's fees, they refused to comment, even in Court.
I know such cults often bankroll litigation by their members or other people, especially when there are controversial issues. The law I litigated under is somewhat controversial, and given their supernatural-based rabid opposition to my sexuality, you just go and do 2+2.
How long they've been involved, I would not know, but I suspect it to be at least for a few years.
They would be rich pickings for such a mob, as they are rapidly approaching retirement age and very rich. Plus their anger and disapproval of my lifestyle and sexuality is something that can easily be harnessed by a crackpot cult into convincing them I have a sinful and corrupt lifestyle and its best to have nothing to do with me.