WANTED: Occupancy sensor that is very sensitive

I am looking for a way to determine if a body (maybe at rest or not moving much) is in a room.  My sons don't turn off lights/fans in their bedrooms, and I want a way to do that.  Problem is that with PIR (and even PIR/Microwave dual setups), they don't move enough to trigger it reliably.  My one son works odd and varying shifts, so setting a schedule for it does not work.  My question is:  Is there a Microwave (or equivalent) only detector that will mount in the same area (up in the corner of the room), or can I mod something like the Honeywell Dual detector to alert on MW only (I *think that might be sensitive enough), or is there a better solution?  I have the wiring run to the upper corner of the room, so whatever I get needs to mount there too, and be powered by the Konnect 12v module.

Thank you!!!

dear Randy,

as I know - it is possible to connect microwave motion sensor. I am sure that KONNECTED  specialists can sell this to you.  Important is to understand:  you ( your son) should not move in the bathroom.  When he will enter the room - the light will go on. After a while ( you can set up the time) light will go off.  As soon as you will move the counting will start again from zero seconds up to the time that you fixed before. 

sincerely, egils berins  (security solutions expert M.Sc.Electronics Engineering)