Charlie Brereton wants to remake much of Montana’s disjointed health care system for mental healthcare, addiction treatment and developmental disabilities into something functional, even harmonious. With the backing of Republican Gov. Greg Gianforte, a generous state budget surplus and alliances with key lawmakers, Brereton’s plan is playing out in an environment ripe for reform. Supporters say his take-charge attitude and savvy politicking are reasons for optimism. Critics worry about Brereton’s tolerance for disagreement, and where his ambitious reform plan might leave Montana.