I hope that if he wants to leave it wont be prompted by a skid with Rafael as that would add more noiise and difficulties in possible options. But let's be honest regardless of how good he he is, his time at Everton has felt wrapping up for a season or two. And personally however great he his, the value is IMO still inflated and should be maximized for the stability of the club. If we were more competent his loss might not be as catastrophic but Everton also have a priority to extract top dollar for an asset that is mentally outbound regardless. Holding on to him beyond his wishes might effect the return we get which would be the worst case scenario.
The fears of selling him are more to do with the clubs negligence in reinvesting than if it's wise to do so. Someone above jokes but if Potter was handling that money I would feel a lot better about it.