If I get my Druid to lvl 65, and 2 box with my friends Level 85 Druid, can that Level 85 Druid solo the entire Epic 1.5 with my lvl 65 tagging along and getting the epic as long as I am grouped with the 85?
Or is the Epic too tough that a level 85 Druid cannot solo it?

Depends how advanced the 85 druid is geared/AA'd. Dressed in current raid gear with max AA's? Sure, I don't see a problem at all. I would think lesser level gear with lesser AA count would certainly still doable -- challenge level will vary, obviously.