there are two ways a breaker may be controlled. One is that an external signal, simulink for specialized poewr systems, or physical signal for simscape controls the breaker status. In this case, you can provide this signal to the other blocks that need to know the breaker status. (may need to duplicate logic to check if signal is above/below the threshold voltage).
If you are using the specialized power systems block which can specify break times internally, then it is a bit more challenging. I would recomend 2 approaches.
Easy: use the measurement ports to look at current through the breaker, and when it is below a certain small threshold, say that the breaker is closed. this will be wrong in cases where there simply is no current regardless.
hard: use the fact that you can create a custom specialized power system block to pull the gate signal out to get actual status of the breaker. I took a pass at it and included it below but haven't tested it (v2020a).