How important is it that the red button is updated without refreshing the page?
If it isn't, simply let the the company_update method reload the view.
Pass the activated campaign in the $data array and use that to set the text of the button.
I think it will get very complicated if you want to do that with AJAX, because Grocery Crud doesn't give you full control over the way buttons are created.
If you need more help, please share your Configure controller. Or at least the method that initially displays the table with Campaigns, and the company_update method.
