Oh boy! I do hope I am wrong, but unfortunately this Summer I had my share of similar problems regarding Cattleyas. I am not sure you can save any of the growths with that brownish darkish lower part. Last week I bought some Captan ( from the new Oak Hill garden) and treated some of the affected plants - after removing any dying or dead tissue.
You might want to run this past Jim or Laurel and see what they say.