Well if you want to get technical, and if we aren't in a technical biz then I don't know; I mean, I've seen people fuss over things way less significant than this...the plan still exists until it is term'd; just taking money out doesn't terminate it. So what are the consequences? Well, the doc should be maintained and updated...if not, the plan is DQd, and the consequences would be...taxation of the $0 in the plan, so not exactly a nightmare scenario. But I think there are potential issues with not terminating it and failing to update for SECURE and/or CARES. As a side note, I try to avoid scenarios where "We find out today that he retired and took his money out in February."
Anyway, I'd formally terminate it; don't see it being worth taking any chances...and could have prepared a termination resolution, maybe 3, in the time it took to ask and answer the question.