I flew in the GOM for PHI so I'll add my $0.02.
In the 13 years I flew "small ships" I often flew right down to PHI's cross-country minimums of 500 foot ceiling and 3 miles of visibility. But here's the deal: When the weather is bad, it is never "smooth." When it's "500/3" out, there'll be some areas that are a lot better...and some areas that are a lot worse. Some days you pick your way around, trying to stay in the good areas. Some days it's pretty hard, especially if you have a 50 or 60 or 80 mile flight. Meh- that's the nature of the job. It'd be nice if we all had two-pilot, twin-engine, IFR-capable helicopters, but that's just a fantasy of certain pilots who have no idea of how things work in the GOM.
Have I ever flown into deteriorating weather? Sure, lots of times. Has it ever really gone to hell in a hurry forcing me to make a turn into the sun and climb? Yup. Oh yeah. So...
Did the event as described by the OP happen? Probably. If so, it worked out other than (at least) one scared passenger. How close did it come to being an accident? We'll never know. Maybe "this close," maybe not close at all.
I'll surmise that the OP was sitting up front with a view of the gauges. Happens a lot in small ships; the oil company guys fight for the front seat. So he saw what was going on, knew they were low, knew they were "in deep sh*t" as we say.
Our #1 job is to fly the customer safely from here to there. But it's more than that, eh? Along with that our job is to not scare the customer. I get a feeling from the OP's post that he did not have a whole lot of confidence in the pilot. That was something I had to deal with when I first arrived in the GOM: Some of those oil company guys had many, many years of riding around in helicopters offshore. They knew what was up better than I did. I had to show/convince them that I knew what I was doing. So I'd bet the OP's pilot was a newbie or relatively so.
If I have one comment to the OP's pilot, I would say SLOW DOWN. I doubt they went from "clear/blue and 22" to "FOG!" in an instant - otherwise the pilot would have seen that they were approaching a fog/cloud bank. So he was "probably" bombing along in bad weather when..."Oops! This is bad. Can't go that way."
When it's crappy, we *have* to slow down. It's counter-intuitive sometimes, like when we're getting close to the destination and we really, really want to be there and get this day over with. You shouldn't fly into a cloud/fog bank at all, but if you do you REALLY shouldn't fly into one at cruise airspeed. And remember, a lower airspeed will require a shallower turn should a reversal be necessary.
I've gotten into some really, really bad stuff in the GOM. Anyone who's flown there for any length of time surely has as well. It's how you deal with it that makes the difference between a safe, professional pilot whose passengers have confidence in him and one who gets blasted in forums like this. We have not heard the OP's pilot's version of this event, but let's hope that he learned a lesson from it that he'll take with him into the future.