The general orthodoxy is that Ferny cannot go on for ever, but the reality is that he appears to be doing just that. Our problem is that players like Ferny only exist once in a generation, and we might well have to settle for someone who is inferior and whose all round game just falls short of what Ferny brings to the team. I used to think Dicky Dunne was everywhere but Ferny is everywhere twice!
He will cave in though & Pep knows it, & as you say, it's far from easy to know exactly what to do about it.
You can see, at the start of some games now, he can be caught out as he gets his engine running again. He needs more time off.
Imo, some on here get completely sidetracked with the idea of some ball playing smartarse taking over the job. But we have players already who can do that, if that's all it needs.
The team are showing no ability whatsoever, to adapt & cover the holes, when Fern isn't there, none. We are often flawed defensively even with Fern in the team. Without him, we can be there for the taking. Somebody has to step up & reorganise the team to cover it & nobody has. And a 21 year old Dutch kid won't do it.
It's the defensive side of Fern's game which can't be replicated by anyone else, even Stones so far, irrespective of the fact he's a defender, he can't position himself. Again people worry more that he isn't splitting defences open & doesn't move the ball quick enough etc; all that stuff is far easier to fix, as a team full of flair players, than having a gaping fucking hole in front of the defence, which Chelsea for example still have half the time, with Jorginho playing there, even though their boss knows him inside out & he has Kante in the same team.
If we can't replace Fern, it's 50/50 we are going to end up going less like Barca rather than moreso imo, because we might simply get beat too often, otherwise.