Try the modified run.m file attached. I added a for loop to loop over the three .mod files (you'll have to supply their names), runnning dynare on each and plotting each set of results into the same 12 subplots, with a different line color for each model. After the for loop, the other stuff you're doing (setting the subplot title, adding a horizontal line at y=0, setting axis tight) is done once for each subplot.
You may want to add (a) legend(s) to indicate which lines correspond to each model. Since the legend would be the same for each of the 12 subplots, it makes sense to have one legend for all subplots instead. To do that, you can use tiledlayout instead of subplot, as shown here, or do it with subplots as shown here.
