Why can't one user access his apps and home screen?

I was trying to "protect" my son's RCA tablet (RCT6873W42) by limiting what he can view. He and I are listed as the "users" on it. I clicked something, and he can no longer access his home screen or apps; however, I am able to access mine. How do I fix it so he can access his screen?

On another note, Google is at the top of his page. How do I get that off?