I stopped wondering years ago about who is enlightened because I think it is always motivated by tanha. What we can know about a teacher - beyond speculation- is whether they point to the present moment in a way that helps us to begin to insight such moments. The rest is wishful thinking.
The Anguttara nikaya commentary tells the story of one teacher, after the Buddha’s time, who had many pupils all of whom attained arahatship.
. But he was still a wordling - not even a sotapanna. However, he understood the tipitaka very, very well; knew the letter and the meaning and so was a great teacher.
see (Angutara nikaya Ekakanipata pali (the book of the ones) Nivaranapphahana-vagga (abandoning of hindrances) 6th sutta; about the Thera Gamantapabbharavasi mahasivatthera ). He lived at Yissa Mahavihara and 60,000 students became arahant.
Later he himself attained.
The commentaries explain that examples like this where a putthujana teacher helps his students to become ariya is like the Buddha was their teacher (because the putthujana teacher is using the Buddha’s words).