Is there any particular reason by which you want the BLESS_SLEEP mode exactly?
We are looking to put the CPU and BLE to different power modes: sleep, deep-sleep, low-power, etc. Before, it was required to put the BLE to a specific power mode before also putting the CPU to a certain power mode. So we are trying to put the BLE into sleep mode before putting the CPU into sleep mode.
You don't have to call any BLE specific low power APIs before entering system level Sleep or Deep Sleep modes. Simply configure the BLE component to use low power modes and make sure that BLE stack is on before entering low power modes. BLE will automatically take care of it's low power entry. In addition, BLE will wake up the system from low power modes if a BLE event has occurred that required further processing. Here are some code examples that use BLE and low power modes for your reference:
CE220167 PSoC 6 MCU with Bluetooth Low Energy (BLE) Connectivity: BLE with User Interface (handles a complex system-level low power scenario)
Please let me know if you have any additional questions.