Are you paying him to make the model? Is anyone paying him to make the model?
No.
Almost every single model on this site is made by people who decide to spend their free time making something available to everyone else, for free. Time is precious, and unless someone has been commissioned to make something within a certain timeframe, it's up to them to decide how to spend that time.
If you're unhappy with waiting for something that someone else is generous enough to model, then it's time for you to learn how to model yourself and take care of it. Otherwise, patience is key. No modeler owes anyone on here anything, and if they don't feel like updating, that's their prerogative.