did I kill my brush cherry

So I acquired brush Cherry, I accidently broke the main trunk but only partial-it wasn't a full(maybe halfway through) break. The tree has now dropped all its leaves but he bark is still alive and green. Anything can do?

Where are you keeping it? It likes sun, warmth, & humidity.
If the bark is green on the part above the break, get hold of some cut paste or grafting wax or beeswax. Hold the broken part together as tightly as possible, seal it with wax, and bandage it snugly with florist's tape. If the top part dies, you haven't lost the tree. It should sprout from below the break. Don't overwater it. Let it dry a little between waterings. Feed with houseplant fertilizer.
Remember, a broken tree doesn't heal like a broken bone. That break will always be there. Your hope is to grow new tissue around the break to hold it together. But that spot will always be weak & require extra care.
Iris

Yeah I sealed it then wrapped it with florist tape, its in bright sunlight with a humidity tray

Broken record department. Humidity trays are a myth. In March in Virginia humidity should not be a serious problem. Next winter you might need a humidifier.
Iris