New hypothesis: There really is a girl actively involved, not only as a hireling or sidekick but perhaps even as the one writing the posts here. revcback/favours/whatever is the boyfriend or FWB who provides penis for on-camera sex acts which require one. There is no brother-sister relationship.
This sort of scam isn't new but can be very effective in getting thirsty makes to drop their guard and part with their money once they've seen a bit of verified flesh (because a real life woman won't scam you, right?). Anyone can pay $5 or so to get a sign made from a half naked girl with a timestamped username of your choice but getting someone to do cam sessions is a bit trickier but not when cam girls do it for a living and will happily take people's money regardless of where it comes from. It's been done on here a couple of times. If I recall correctly a couple of people 'verified' that the user codishmumu was legit via some cam session and turned out it was a dude, and even further back than that there was a guy who was pimping out his druggy girlfriend in exchange for drugs off Silk Road, and guess what? Turns out to be a dude and went on to scam someone with a gambling site they launched:
Post them!

What he actually looks like:
yeah that's the faggot. Ron isn't his real name. I would link his real name but you guys would dox me in a heartbeat if I did.
What caused you to sever ties with "Ron"?
I really don't wanna talk about it but if you guys really want to know I'll give a little details.
And there was his 'homeless Jackie' scam before that which was later found out to be him:
Hey all!
Just found a chick who likes (1)Bitcoins, (2)Chats on the forums about anything, (3) I Dont think is a lesbian!
Check out her site at:
http://homelessjackie.com Her Bitcoin Donation Address is listed here:
http://homelessjackie.com/bitcoin-donations/Come on people this is from what i see a first time real world chick! get those bitcoins going!
Does anyone have the verified pictures of the alleged alia girl? This scam certainly reminds me of the above one and the guy is a long time scammer going back years who I doubt ever went away.