God silences Satan by choice. But He doesn't do anything else to Him. Satan, after all, was 'just doing his job,' being the prosecuting attorney.
It doesn't make him a 'fallen angel' or Babylonian Lucifer. In Judaism, Satan is very much part of the "God-Squad."
It says God rebuked Satan. Satan went beyond what God allowed and that is sin. There is no grace for the sinning angels for there is no sacrifice for them.