I'm very glad he is eating and that may help deter him from your corals but it could also spawn a mass coral slaughter. If his digestive system is just now allowing him to eat then he could start taking bigger bites out of the coral.
50/50 chance.
As for your luck.
Yeah, lucky is what you are. But advice given; take what you will from it.
Does the place you shop quarantine or something? Not saying that every fish and coral comes with need to be treated but that is a fairly uncommon practice where I am from. Almost all places I go has an aptasia, the occasional parasite, or simply lack of knowledge that would require research before purchase. Its just not a good business making practice. For the in home aquarium it is dirt cheap to quarantine which is the assumption the lfs usually have.
I wish you luck. Any other questions you have I'll be glad to answer regardless if you accept it. Just remember, we take these fish from all over the world. If you move to another country with say your do or cat, they quarantine the animal for 60-90 days. This is for a good reason too. Disease is microscopic.
Another analogy to persuade you towards QT. lottery tickets. How many times can you win your money back before you finally loose? The odds of losing outweigh the odds of winning always in the lottery.
Ok. One more. Russian roulette. One bullet in the chamber, how many times can you pull the trigger before it shoots?
We at reef2reef and any other forum (as a majority) believe strongly in quarantine and care. We do not make commission off any decision you make. We are here to help you buddy, if you want to risk the lives of fish and corals that is on you and you alone.
Might I ask you what is the reason you keep resisting this simple procedure?
"Live like tomorrow already happened. Yesterday is only 3 days ahead. Today will be here soon."