I had this problem with my Samsung J3Emerge after dropping it in water, and it was simply fixed, through my home button still doesn't work. I just did the following:
Put my phone on the charger.
Settings>Accessibility>Dexterity and Interaction>Assistant Menu>Device Options>Power Off.
Next I simply held the lock button until it turned on. The lock button now works and the home button can be accessed through the assistant menu.