I'm guessing you have read this already but since it's a new thread, going to jump off of your post to post it again
I don't know the answers to your questions, the only thing I can gather from what we "know" is that it was very recent, 2 weeks previous, that he "confessed", and afterwards, he started threatening her and she was afraid of him. I thought it was said that they were childhood friends, but I am not sure, could have even been high school friends. If I can find that video again I will post it, I'm sure Maline had more details than what I copied from the overhead.
From Defense OS (was on overhead screen):
Tracey Riccobene
October 26, 2018 went to investigators and defense to give statement.
Dan confessed to her that he murdered the family
Detailed statement
Held one of the boys at knife point to get the family out of the home
DK raped Summer
Wanted revenge against Joseph McStay for cheating him
DK buried the sledgehammer in graves
Was not in Hawaii - DK lied and provided false alibi
DK came back to the house and pretended he was Joseph
Known DK for years - Best Friend
Like a brother to me
Share music in common
Says DK is a genius manipulative mastermind
Full confession 2 weeks ago but had been hinting at it for a longer period of time
She told him to come forward - he refused.
After Riccobene told DK to come forward
He has been threatening her
She is terrified of him
He has no empathy toward other people
She feels it is her duty to come forward even though DK will harm her
Requests witness protection