Bachelors thesis supervisor headed for emeritus; professorship won't be restaffed
You already gave a good summary with the three questions at the very end.
If you are very interested in the topic, already know a lot about it and can work on your own without much help, then go for it.
If I were you, I would sit down and try to figure out a topic for your thesis. If you have the impression that you have a reasonable idea then ask the professor if this is ok for him. If not, I would think about going somewhere else where you get more supervision.