I get the strangest feeling that the old ass & sick king is the ex lover of Realia's Mom. It would make sense if he was hiding out incognito and fell in love. Perhaps, he wasn't the direct heir or wanted to live a commoner's life doing good, or wanted to protect the orphans or something like that, but then suddenly he either got injured or something. I say that because of the hair color.
It would be interesting if the King somehow managed to either run the orphanage in secret or something like it. I say that because the guy "mysteriously vanished/disappeared" without a trace. Stories of nobles or royals hiding out amongst the commoners is ages old. So, it wouldn't be unexpectedly novel a plot twist. Hmm… 🤔