Yeah Claudio Ranieri achieved a complete miracle with Leicester City last year but as Mourinho has brilliantly put it recently 'There is no loyalty in modern football'. The board doesn't care about him, they care about the results and if Leicester get relegated for real that will be a disaster.
By the way I have heard that they are going to erect a statue of Ranieri in front of the stadium. I am not sure if it's just rumors or a real plan though.