Cheap and easy headliner repair
This isn't a top quality repair, only total replacement would do that, but it'* easy and gets the godawful headliner off your head.
Go to any fabric store or wherever they sell slip covers for furniture, and ask for the spiral pins with plastic button heads that are used to keep slipcovers from moving out of place. JoAnn Fabric or Bed Bath & Beyond are a couple of likely places.
I bought a package of 20 or so for a couple of bucks, and used them to tack the headliner back up every 6 to 10 inches in a diamond shaped array. They pierce the headliner backing, screw down snug and have stayed put for several months now.
I hope that'll be helpful to some.