I'll be on the job market this year for teaching positions at very small schools or lecturer positions at large schools. I took a class about two years ago now that was focused on teaching pedagogy. It was great, and I had good rapport with my teacher. After the semester, I asked her if she would mind writing a recommendation letter for me in advance, despite almost two years until I would be on the job market. The intent was that I could contact her when I was actually on the market, and she would already have something prepared from when I was in more regular contact with her.
My professor did write me the letter. However, she also let me know that she had recently received a diagnosis for a debilitating illness that would be demanding her time and attention, and sent me the letter she completed. She's still alive, although on leave indefinitely from the school to concentrate on her health and spending time with family.
I'm wondering what the protocol is for whether I should use her letter or not, particularly given that many schools prefer to contact the letter writers directly. I come from a big research school, and while other professors would be a great testament to my character and research, none have any real awareness about my teaching. A few schools I'm considering applying to actually specifically ask for one letter that focuses on teaching.
Given how teaching-centric my job search is, I think her letter would be a great asset. But I'm not sure whether I should use it, and if so, the best way to get the letter to schools.
Note: This is for the US academic system.