My gelding just shed his frog a few weeks ago (first time I had witnessed that in nearly 20 years with horses). It looked nothing like those photos. It was a layer that peeled back off the frog, and did require a hoof knife to disconnect from his heels. But when it came off, he still had a very distinct, undisturbed frog underneath.
To me, your horses hooves look to have something more serious going on. Is he sore at all or do the feet have any smell to them?