It's possible to make a 3D html5 game for mobile in construct with the plugin he mentioned. I'm doing that at the moment. But you need to be aware of the limitations of phone hardware, so you need to be smart when how you build your game. No complex shaders, no realtime shadows, not too many lights, etc.
And also, you need find a way to work in the editor. Since Construct does not have a 3D viewport, it's a bit tricky to build your levels, but it's doable.