[ "That's just it" seems like an understatement for what's basically the weight of the entire universe on John's shoulders. There was a time where Ryoji tried to sway Minato's hand over something somewhat similar, but he has no stock in John's problems, so this is where he leaves it at. ]

I see... Well, whatever choice you end up making, there is no wrong answer. It's a choice, but one like the sorts you make every second of every day, it is what it is. Things will work out.