Most likely the "Back Plate" ribbon cable has been damaged. I have seen this several times where the home button and its ribbon cable are fine but the cable that runs on the back of the back plate no longer works. You can confirm this by replacing the back plate and ribbon cable only.
There is a chance that its the home button but would not know until you have replaced the back plate first.
Please reply back after trying this to give an update.
Best of luck!