He made a personal decision to step back from the forum for personal reasons and had informed me & the other mods of this decision at the time. Much had to do with his need to take care of elderly relative (a father or father-in-law?) and just felt he had too many other personal things that required his time.
If there were any other reasons, like maybe I or someone else here did something that upset him, he did not mention anything along those lines to me, so I can only assume he just needed to step away to focus on other things.
That said, I will add that Nial was a prominent presence here for several years and helped me in countless ways to maintain a people-friendly forum, serving as a moderator for several years. While I respected his decision, I was certainly sad to lose him as an active member.
He still has an account in good standing & I'll forward this thread to the email I have on file for him. If it's still a valid addy maybe he'll pop in to say hi.