I dont think Barr considers Mueller to be his friend anymore. Barr seems to be the kind of guy who maintains friendships with amoral people who have no integrity. Id bet in one of the meetings that Barr told Durham to go where the facts lead, and to not cut Mueller any slack. Barrr has got to be posies of at Muellers betrayal of his trust.
Sessions, OTOH, was playing by Senate rules...esteemed Senator, etc. He was never going to be aggressive as AG.
"posies????" I don't think that makes sense.