A yes man? A cone man? Is that what he is?
I am sorry, I thought he was an assistant coach. Someone who was meant to offer ideas, challenge the manager, become a link to the manager for the players.
If it is the latter he has failed miserably 3 times. If its cone man and yes man then great, keep him there, but let's not pretend he is anything more.
There is a reason assistant's go with the manger wherever he goes and generally do not just stick around to work under manager after manager. He is on his 4th regime now. Its weird.
Just make him the bloody kit man or an ambassador if it's that important to have a token ex player around the place.