Yes, that's a tough one. Might be, if you feel like you owe him an explanation why you are unwilling to help, other than what you knew before you read the police report.
Or it might be better to just let him wonder if you guys have eyes in the back of your head or psychic powers or something, because (based on my prior experience) it just opens things up to more discussion.
"Why did you tell us you were going to plead not guilty when you had already told the police you had done it?"
"I was scared of the police/the guy I was with made me take the blame/I was hungry and not thinking clearly/I thought I was fired and was trying to come up with money for rent so you wouldn't be disappointed" etc, or whatever he would/could say to get you involved again?
I don't know...but I know my son would find something. He's good at it.
But I truly don't know, Lil. Just musing on my part. I'm so sorry you guys are going through this. I know that feeling so well of being ashamed, and to have it with people you see professionally on a regular basis really sucks. You guys deserve better.