Re: Naugahyde Vinyl Headliner Question
"....he said eventually...the headliner will probably come loose. Has anyone had that problem...."
Well yes, eventually the foam gets old and brittle and disintegrates and the headliner sags down. Islander used foam-backed vinyl in their boats, some of that lasted 25 years. Unless foam rubber is "nitrogen blown" (made fiizy bubbles from gas under pressure, like soda) you never know how well the chemicals will age, and the cheaper mixes all become brittle and turn to dust. Car headliners, boats, even upholstery padding.
From what you say here, I'm guessing he didn't quite realize how many battens or pieces he'd have to use to cover your overhead, or if it can be successfully covered with something relatively thin that "telegraphs" every imperfection.
Maybe it is impossible, but I'm guessing he made an estimate without really doing his homework, and now just wants to back out of it because there will be more work than he figured. Good upholsterers are hard to find, but I'd try to get another opinion--from someone who comes to see the boat, or at least sees lots of good pictures of it.