I've certainly heard of Boerboels and Boerboel crosses being put down for "excessive handler aggression" - but none because of excessive handler aggression in old-age specifically. Both example I've heard of occurred after 1 year old, but before 3.My only concern is I've yet to hear of an elderly boerbel here in America. From what I hear they turn really aggressive when they get older and have to be put down. Their sole duty in their country of origin is a guard dog par none. Same category as a Fila (from Brazil and often called the Brazilian mastiff).