Are you sure he has a Gold Question Mark over his head?
Yellow Exclamation Point – This character has a quest available for you. Walk up to him or her, type “X,” or left click to talk and receive your instructions. You can see a picture of this on the next page.
Gray Question Mark – You are currently working on a quest for this character. The quest will appear in your quest log, which you can access through the menu, or by pushing ‘Q’. The box in your log tells you where to go to complete the task, what your task is, the rewards for completing the quest, and tracks your progression.
Yellow Question Mark – You have completed the quest for this character and simply need to talk to them to finish it and receive your reward.
I am having the same problem.I got all the yard birds,oysters,and smiths.I am now in DS and when i talk to Zeke there is a grey exclamation point above his head.For some reason i cannot get the quest.Can someone please help.Thank You~ Madison Icegem