Half turn screw. See if it pulls tight or if it dose nothing as board had crumbled a bit.
If board around screw has failed and crumbled fit another 38mm drywall screw about 25mm away.
I use a large drill or a countersink bit first to dip in surface a bit so the new screw head sits nice.
Toupret powder filler. Sand. Fill again if needed. Sand again and paint.
To find joist direction tap tap and you will hear the thud so will know which way the joist runs or use a magnet to find the other screws.
No need to drill pilot holes.