Brat has always been saying he likes team sports better than individual. Maybe his on-court antics are frustration that he has do deal alone with mental pressure, and he cannot. He was doing good, and saying he was feeling good in OZ Davis Cup matches, as well as in Laver Cup matches. So it does not even matter whoever is in the team as long as he supports him on the court.
Eventually, brat should become doubles specialist. Money will be smaller, or maybe not if he finds someone to become no1 team like Bryans rather than hanging around no20 in singles as he does. But overall much better situation than accumulating frustration that he cannot deal with, and facing fines/career disruptions for his antics.