Clear all the data of google app then
Go to play store > options> My apps & games.

[![My 'Apps&games' >][1]][1] 

[1]: https://i.sstatic.net/3JG6Z.png

Go to 'installed'>Google app > uninstall

Now don't do anything it will show to two options 'update' and 'open'
minimize and close play store.

Then head to the settings > storage & USB > internal storage > Go to google app.

Now you should be able to disable it.