Vernon decided to put the boys in therapy before he loses his mind. And he was at his breaking point. He took the advice to keep them into individual therapy for now. He wished he could know what they talked about, but that would be unproductive.
Harry sat in the office. "Mr. Potter, you have had an interesting childhood." Harry stayed silent. He would not give the therapist ammo. "Vernon has informed me you are still a very suspicious child." Nothing, but his eyes glanced at her for a moment before he turned back to his downtrodden and cautious expression.
Dudley was a little more cooperative with his therapist. Vernon hoped giving them separate therapists was a productive move. It's not like there's a guide for this situation. "I miss mom. And Harry caused it! Dad would've never divorced her if it wasn't for him!"