Oke i just had a oneplus2 come in for this issue ..come to find that its a software issue.
Solution 1 (only works if hardware is not damaged)
Root your device.
Download Root Essentials app from Google Store.
Open Root Essentials and head to fingerprint gestures and turn it on and test your home button now.
If the button works , turn off fingerprint gestures from root essentials and head to security setting to set up fingerprint.
Solution 2 (NO HARDWARE DAMAGE)
Install Custom recovery
Flash RR Official
Root your device.
Download Root Essentials app from Google Store.
Open Root Essentials and head to fingerprint gestures and turn it on and test your home button now.
If the button works , turn off fingerprint gestures from root essentials and head to security setting to set up fingerprint.
Make sure your Home Button is not physically damaged from botched repair.
If it worked please write here to help others.
You're welcome.