Kawa1400, I'm really sorry that you lost a friend. The AAIB (Air Accidents Investigation Branch) report will eventually be published. Details here
It looks as though you can sign up to receive email alerts from them; I've never done it, so I don't know how that works. Maybe someone else here will. But I know that reports sometimes take months to be completed.
As for what happened, it's all speculation right now. I do know that even careful people sometimes make mistakes or act out of character. We all do, but only in aviation does it tend to be fatal. I've lost friends that way too.
Did he turn back? The report may be able to comment on that; I'm not sure. They can probably find out which direction the helicopter was facing when it crashed...or maybe not. He could have been off course, especially if the weather was bad, and even a small mistake like that in Snowdonia can be fatal. I really don't know, and I don't have as much experience as some of the people on here.
I'm sorry if you've been upset by some of the comments here. Bear in mind there are all sorts of people on these forums - real experts, some who know rather less, some who know absolutely nothing, plus people who aren't what they pretend to be. Yes, and dick swingers too! It's the internet after all. But one thing most of them have in common, maybe, is a tendency to assume that they're talking only to helicopter flying colleagues, not people like yourself. We shouldn't do that, but it happens.
If you stick around long enough you may find out something useful on here, but don't bank on it.
Sorry I can't be of any more help.
Whirly