Just a personal experience....I had my pin cushion lose almost all of his pins due to a salinity issue in my tank. I had my salinity up around 1.030 for several months due to a bad hydrometer. He looked pretty bad but he kept moving and I could always see his sweeper tentacles. His activity never changed but he looked like crap. Anyway, after correcting that issue he has slowly recovered. This all happened in July and he is almost back to normal now, but still is regrowing spines.
I would say contact live aquaria cause it doesn't sound good. Hopefully you got some picks of the brown water he arrived in. Is he giving you any indication that he is even still alive?