drush error - how to apply patch?
Drupal has a wealth of community documentation related to this:


Patch guide
Applying patches
Applying patches manually


However, for your first problem. Drush is pretty much version independant. If you have the latest version of drush it will work with drupal 7, 8 and most likely 6.

Finally, the issue you linked also mention that it's been fixed in the latest version of drush as well.