I wouldn't rule it out, actually. Harris became friends with Beau Biden when Biden was the AG of Delaware and she was the AG of California. They worked closely together while they were in office and used each other as sounding boards. Could be a simple convenient media narrative, Harris reconciling with her dead friend's father in part because of the admiration the younger had for the other, but it's also extremely plausible. And, it's not like the elder Biden didn't develop a close friendship with the President he worked with - their bromance is the stuff of legends.