Tell your boss that Visual Composer is the cancer of WordPress. Tell your boss that you've separated content concerns from visual ones, and that you're not tied into an abhorrent shortcode nightmare should you ever wish to move away from VC and/or change the layout.
To elaborate, "VC vs ACF" isn't really a question - they are two completely different products. You should make that clear to your boss.
One is an end-user product for creating "beautiful" websites "without knowing any code" i.e. you might as well sign up at hosting company XYZ for their "website builder" because you're gonna get the same quality of product at the end of it. Not to mention that you need a degree in engineering to use it - it is horrific. I honestly can't imagine a real "end-user" actually getting on with it. If I were to build these kinds of sites and then hand them back to the client, I would never sleep. I would be barraged with "how do I do this" & "how do I change X" emails 24/7.
The other, whilst anyone can use in principal, is primarily geared at designers & developers who wish to create beautiful interfaces quickly and easily, dealing with your data & content concerns in the backend so that you can create beautiful, accessible, semantic websites on the frontend.
I'll leave it up to you to guess which one's which.