I agree With Ben on this one you need to replace the home button which up till a few weeks ago was a death sentence for your phone but you can now replace the home button and not end up with error 53. you will lose the touch id function of the home button when you replace it but there is a fix for the errror that will come up when you update the phone after replacing the home button
https://support.apple.com/en-ca/HT205628
a help for replacing the home button
[guide|24983]
replacement part
[product|IF124-013]
Hope this helps