I am sure theymos will be gone one day like all of us, and it will happen sooner or later, but I am sure he made some backup plan of people who would take over control over domain and forum.
It would be surprising to me if he hadn't done so already, especially if he's really the sole person in charge of bitcointalk. Theymos is no dummy, and I know he cares about the forum--so those two facts combined make me think that he most likely has an heir (or more than one heir) in the case that dies or is otherwise unable to continue being the administrator.
It would be interesting to hear something from him and even his confirmation would be good enough, so maybe team of trusted admins and mods would take over or his kids and people he trusts in real life.
It sure would, but I wouldn't hold my breath waiting for him to weigh in on this. I was hoping he'd tell us something about how he thinks the merit system is going, but instead he just created more merit sources and upped the existing sources' sMerits. I guess he's a man of few words when it comes to certain things--and my guess is that the issue of succession is one of those that he'd prefer to keep to himself.