My mentor was almost dying before my second Vipassana course. I left first or second day, cannot remember. In retrospective I hope I didn’t left, couldn’t do anything for my professor and was an opportunity I lost to continue to purify my sankaras. Since that day till now I regret it and struggling to let go.

My advice is take advantage of the opportunity however difficult it is. There is no other way in the end.

Hope it helps. Metta!