Has he been sacked or has he resigned? There's a big difference. If he has been sacked then Sadler has potted the wrong man. Maybe the job was too much on top of everything else and for not much money; £15k a year is a pittance. Like Tinm said, he's had enough after 4 months.
Something is happening at the club though. Too many negative things going on and Rest was right about one going first and the other would follow after a massive fall out. I wouldn't be surprised to see BB gone within the next 7days too.
So, if that happens we have no board, no manager and come June a handful of players, league 1 and an unhappy fanbase. Not exactly the position we want to be in at the end of a relegation season is it? We are now in a worse position than when Sadler bought the club because he is right back where he started without any support like he had then and the feel good factor well and truly gone. I'm not sure how he is going to recover.
Oh, and edit to add, it certainly wouldn't have been Geridty's decision to take on Appleton or MM, those decisions have to have been made by BB and SS and ultimately SS.