oswald MIA

playing local co-op with my partner and we are in Act Three - Oswald has not been available when we are playing co-op. Oswald only appears in the encampment when my partner is logged in solo on his monk or mercenary, but when I log in solo to my witch, Oswald is not available. This has become a problem as when we were playing together (mercenary + witch) Oswald only showed up for the monkey god quest. Now i have this quest item in my inventory that I cannot stash or return to Oswald because he isn't in camp and he won't accept it outside the tomb where he originally gave us the quest.