Some context: Person A and Person B both went through a trying situation dealing with Person C, someone that Person A has known for many years. They are now talking about how awful it was. Person A then thinks this:
which as far as I understand is something along the lines of: Person B has suffered 10 years less than I have. How lucky Person B is.
I was pretty surprised 人間 was the choice of word here. I would have expected 人 instead because in my experience 人間 refers to humanity or a type of person. Is this something that's done frequently?