If his tentacles are nubs don't try to feed him. He can recover but will need substantial light. Also, you will need rock steady pH and temp (the swings seem to really hurt BTA IME).
Temp, alk, calc, mag (if calc, alk and mag are off your pH will be too), pH and lighting info are all necessary info.
Also like worm said flow type is important, these need moderate, and usually indirect flow, across the oral disc to be happy.
I have purchased two bleached BTA in the past and both recovered and colored up within a month (however tips were not nubs). More recently I had the thermostat malfunction on my heater, causing 4 degree F temp swings a day and 9 degree F swings in a month (by estimation), took me a while to figure out what was going on (moral is don't solely trust your heaters digital thermostat). After 3 weeks of this I almost lost all 3 of the current BTAs that I have. One was starting to lose tentacles, one was bleached with nubs, and one spent 50% of its time as mush and was bleached with no tentacles. 2 weeks later one was almost fully recovered the next had color back and the nubs were 50% larger and the third rarely turned to mush and had bleached tentacle nubs. 2 weeks after that the first was recovered the second was regrowing tentacles and the third was coloring up with noticeable growth in the nubs.
I could keep going but the point is that with stable parameters high lighting and no feedings the nem should show signs of recovery in about 2 weeks and substantial regrowth in a month.
I made no attempt to interfere with the anemones as this will stress out an already substantially stress nem. However, mine rarely moved even while severely stressed (once temp was fixed that is) which leads me to believe that something about your tank is still stressing the nem whether it be light, flow or parameters. If it is light or flow I would recommend catering these to the nem rather than the other way around by trying to move the nem unless it is on a small moveable rock.
Remember, BTA like to have their foot in a rock crevice and extend their disc into flow and moderate to bright light, a BTA in a suitable environment (even an unhealthy one) should not move more than slight readjustments. I am not really an anemone expert but I have substantial experience with BTAs and have recovered many, hopefully this info helps.
