Do the parents and kids know or recognize each other several years later that would be remembering them can they do this?
As far as we can tell, when adults do come across their kids elsewhere or on territories after a couple of years, they treat them just like stranger peregrines. It might be that social behaviours learned from their parents when they were chicks makes them more or less threatening. More threatening because the behaviours they learned are the same behaviours the adults use. Less threatening perhaps if the behaviour is appeals to the resident bird. But no way to know any of that, its pure speculation on my part. What does seem to be the case is that other than mates, other peregrines are threats or potential mates.
