The only argument you can likely make (unless his code just doesn't work) is the maintainability one. If management doesn't go for it then they actively don't care about maintainability as much and as offensive as that might be to you as an engineer it is their choice to go down that route.
Overtime your style will win out if it truly is the superior choice for their needs. The parts that you coded versus his should be easier to refactor, debug and have less general issues overall. If this is not the case then your assumption that your style of code is better than his may be wrong (at least in terms of the company's needs).