Twisted I apologise in advance as I've not had a chance to look at your other links. I have however had a chance to look closer at the first website you posted. The 'magic drug' it refers to is nalfemene (Selincro), not naltrexone. Very similar actions though. This drug is known about, and used, for moderation in harmful drinkers. It's prescribed either by GPs or DAATs, which will probably vary by locality.
I haven't read enough about the Sinclair method (I will have a better look tomorrow) to say it's used in 100% the same way, but from what I've skim read it is extremely similar. The key difference from what I can see is that, as per NICE guidance, it is given in conjunction with psychological support. The (substantial) evidence that supports the guidance is outlined here www.nice.org.uk/guidance/ta325/chapter/1-guidance
I don't doubt your intentions, and please don't think this is an attack on you, however speaking personally that first website you posted got my defences up. Everything from the fact I eventually found the name of the drug on offer under the 'family and friends' section, to the 'buy your own blood pressure monitor for your home detox' rang alarm bells. I have a strong suspicion that it is either run by someone with good intentions but a poor understanding and application of evidence based medicine, or someone simply out to make a profit out of vulnerable people by hard selling something that is already essentialy available. It also massively oversimplifies a very complex and individual issue.
I genuinely think that if your acquaintance is serious about wanting to try this they should have a think about referring themselves to their local DAAT or speaking to the GP in the first instance. They will be working within guidelines which are regularly updated and reviewed with the best available evidence, rather than biased towards one magic cure-all.
Like I said, it was the website's 'hard-sell' that has got me on the defensive, and not you personally, so please don't take offence to my ramblings!