Here is a list of steps to help you fix a broken or unresponsive home button:
- Backup your important data.
- Restart your device.
- Go to the Settings and check if the home button is enabled.
- Check if the home button works in some other application.
- Update the software to the latest version.
- Reset settings to factory defaults.
- Take your device to an authorized service center, if the issue still persists.
If professional help is not required, you should also try a few home button related troubleshooting steps like cleaning the button, restarting the phone few times or trying it using a bluetooth or external keyboards.