That may just have been him waking up and deciding he was in danger, so please don't hold that against him.
The hens would be heartbroken if they lose him, it sounds like. And yes, I have seen heartbreak in animals, even chickens, before. They can and do just give up and pine away, after losing a dear friend, or after a big shock, or something like that. I have saved them before, sometimes, and sometimes, I can't.
Back to Harvey... you may have to choose whether to force-feed him or let him go. They will waste away, and become very weak, and then just stop moving at all, and then die. What you can try is to get some baby vitamins into him (the variety with no iron), because only a few drops is all it will take to really help. The Rooster Booster or the Durvet vitamins and electrolytes won't help if he's simply not eating. The few drops of baby vitamins will.