I'd give it a poor chance of actually being satisfactory and working well enough to trust the brakes. The brake mounts will require spreading the frame, and depending on how thick they are, will interfere with full engagement of the axles with the dropouts. Any flexing between the mounting bracket and the frame / fork may cause them to work loose over time. And it may be quite frustrating to remove and replace the rear wheel to fix a flat tire. This has the looks of an aftermarket accessory that is not fully engineered for your bike.

What's wrong with the brakes that are already on the bike? This "upgrade" may be a step backward.