HI there,
Ok, So I can say when I tested the Similar unit (mm/wave) , I had to do some strange connect at one Baud rate then Change it in the BLE trick/procedure for the App to work (the raw data is there), once I stumbled through it, You’ll see in the video posted, it worked well and was very accurate and repeatable.
There is also a Youtube video, with the setup and it’s working above a man in a chair 
He get’s up simulates the fall down and it’s detected as well as he is breathing kinda thing. It is an asian video not sure where but for a convention on medical devices.
More and more of these are coming out and so is the Science behind how they actually work, keep looking you’ll find it out. I’ll look and post back if I can find it too.
HTH
GL 
PJ 
ps. the main take away was it had to be very sturdy mounted two or some inches below the ceiling (there’s a drawing in the wiki or datasheet for the sensor) and the detection box calibrated to be 2 inches off the floor with the far end of the measurement zone. if that makes sense. 