Yes, he's looks pure bred. Did you buy him with AKC or UKC registration? CKC or other registration are not reputable. Truthful, the only way to really know is DNA testing. Don't get discourage if he doesn't have paper or does not meet standard. I believe you have already love him.
Like I said above, just take him to the Vet and make sure he's healthy so you won't have a lot of heart ache later.
As for your second part of the question on how to work with him. Please be more specific like behavior/food/care/sickness/etc... I would start it on another topic so more experience Yorkietalk member can hone in on it to help.