Axl can hire another guitarist
Unless the next guitarist is Guthrie Govan, I very much doubt they can find a replacement that can play Ron's fretless/fretted stuff before the European tour. And I doubt Govan would fill in either, unless Ron asks him himself.
And why can't DJ handle the sound alone? I never understood why two guitarists are needed anyway.
Dude barely can play Finck's stuff, let alone Bucket's or Ron's. He can't handle the sound... simply put.