Can android devices be controlled/tracked (including on/off control) by IMEI? Phone lost having sensitive data that cannot be deleted, The owner(my cousin) has gotten mentally unstable. Tried every possible solution to track it like google's find my device. I also tried to track it by the service-provider/carrier number but couldn't achieve any result so the SIM card has been blocked/disabled. Lastly I reported to the proper authorities to track down the device but strictly advised not to erase the data. They asked for IMEI-number of device which i provided to them on spot. No response whatsoever has been recieved that could even provide a grain of hope for recovery. My cousin is considering sucide but only me being a trustworthy person for him have been controlling him by giving him lies and false hope. The device has not been connected to the internet or even turned on since lost so that it could be tracked down (info by google's find my phone app). The authorities told that it can only be controlled or tracked by its IMEI-number. IS IT POSSIBLE
My email-id is/was also activated on that device. Proper documents and all original accessories along with box and IMEI sticker can be shown for proving ownership of the device
Device: LG-Q60
YES Any phone could be tracked and localized using its  IMEI  but to successfully do it the stolen phone should be online by:

Internet connection
Sim card inserted

But if the guy who got your cousin's phone could change phone's IMEI(and for sure phone identity) : Sorry to tell you that the phone is gone forever.
The best solution of all times: daily cloud sync.