Hi Kim, If I understand the sentence correctly, "although there's not a whole lot" refers to "his presence", as in "his body in the room with us". So, it means that there isn't a lot of his body. Like, he's thin. Without more context, this is my best guess.

You can generally say "There's not a whole lot"--it just means there is little of something, like if you pick up a carton of milk and there isn't much milk in it. But if you use that phrase, it would need to be clear what you're referring to; otherwise, you need to say "there's not a whole lot of milk" (adding "of" + the noun). In the sentence you're asking about, it's not clear what there's not a whole lot of--the author is probably indicating that there isn't much to Jeremy's presence (maybe he's small or thin, or he has a boring personality, or he's not staying very long), but that's only a guess, because the sentence isn't clear and looks incomplete. It may also be helpful to note that "in person", "with his presence" and "in the flesh" all mean functionally the same thing, so it's odd to put all three together.

jeremy didn't presence a lot