Busquets needs to be transitioned out of the XI over the next year, it has been clear since Valverde got sacked. With that in mind, the difficult thing is he is probably the one amigo left in the squad outside of maybe Alba that is still good enough for lack of a better term, despite their obvious shortcomings.
With Xavi, it is pretty straight-forward for me: the best 11 players should and will play. If Busi is the best performing pivot, he should still start him but the key for me is actually trying de Jong and Nico in the pivot for a few games. That is the only way we can fairly evaluate all of this and as long as Xavi does that, I will be ok. If Busi still looks the best in that situation, he should still play but I just dont believe that if either Frenkie or Nico clearly look better than Busi, Xavi would still play Busi because friends.
He stayed away for a long time for a reason and if he wasnt ready to put aside his personal friendships with some of these players for the sake of the club and his job now, I think he would still be in Qatar.