A lot will vary in how easy he will be to tame including his personality and how well he's been handled previously. The biggest issue you're likely to come across with a Chinese is that they can be a little bit shy but with a bit of patience, there's no reason why you shouldn't be able to tame him.
I've managed to tame a pet shop Chinese in a few days but I've also had one that took about 3-4 months as she really was quite nervous. Males tend to be a little bit more easy going than females but do have a tendency to be a little bit lazy.
When you go to visit him again, watch how he reacts to being picked up and held and that should give you a good idea on how trusting he is of people and what you might need to work on with him.
Do let us know how you get on.
