What is the relation of Hetty and Callen?And in which season we will learn it?

Callens mother worked for C.i.a Hetty was her handler
Hetty was on the strand when callens mother was shot as a kid callen was also their at the same time hetty bought callen back to the us and placed him in foster care But she's been looking out for him ever since as he was older hetty asked callen to Mitmachen Navy CIS BUT BUT callen didn't know hetty knew his mother if that makes sense LOL