iphone 4s wifi greyed out what should i do

You linked from the only support document known about wi-fi being grayed out. Given that you are speaking about a phone that was released 6 years ago, I suspect it is very possible that the wi-fi chip has failed. If you have followed all of the steps in that support document, you can make a Genius Bar appointment at the nearest Apple store to have the device examined by Apple. They will explain your options from there.