playing devil advocate... err.. CIA analyst - the son would probably wanted revenge and would get "radicalized" by the murder of his father. Vendetta for that reason is pretty much killing all (male) members of the family, including children.
Wait wasn't that the same reasoning Nazi's used when gassing people (i.e. why the prefer killing families). That way you are safe from Vendetta. If you have to worry about Vendetta from those you afect with your drone strikes, you are doing it wrong.
Uh oh, does that mean we're about to see the families of all the collateral damage get wiped out too? And what about their families... what about Kevin Bacon...