I don't agree that flying someone else's private helicopter is a good choice. He will wake up one morning and the market has taken a downturn, and sell the helicopter with no notice, leaving you unemployed. If you plan to fly for a living, fly for a company whose core business is flying, not for one (or an individual) which flies as a sideline. I've seen it happen many times.
It's always a concern and you need to choose the company, just like with any other business, including aviation companies who also suffer in any downturn.
However, flying for private owners has certainly kept the wolf from the door for me for the last 7 years. Yes, if the heli goes, so does the pilot, with a months notice, btw, as per my contract. Three months with the last employer and in that case it was me that made the decision to move on. I could always move elsewhere, just like any other job.