There's a class I would like to take, because the professor's research interests me a lot + he's pretty prestigious in his field, and I would love to form some working relationship with him. But I have reservations, because his research output seems to have dried up in recent years, and he's *really* old, indicating that he may retire soon.
1. Is there a way to get more certain information on this that I'm unaware of?
2. Is it common/possible for professors to write LORs after retirement?