depends on his long term goals, but if he just wants to maintain an honorable discharge and GTFO, i would get an attorney and go with scorched earth. if he wanted to stick around, it'd be one thing, but it sounds like his military days are likely over. i would simultaneously go EO and congressional. you've never seen these former "sheep dogs" turn into wet noodles faster than when a congressional comes in. keep in mind though that a congressional does not create a solution, it merely has a time sensitive "response" to what the situation is and is almost like a "status report" of WTF is going on. once he creates enough wake/turbulence, they will either PCS him or accommodate his issues. too bad we don't have unions or they'd do all of this for him, and enjoy it to boot.
hope it works out for him
--your friendly neighborhood sherman had the right idea caveman