For my intrusive thoughts I acknowledge them as a bit sometimes very weird and remind myself that everyone has them. It’s how you deal with them. If the thought persists and won’t go away with acknowledgment, I visualise them as a tissue (generally red for me, any colour will do!) I’m holding in my hand in a breeze, and once I’m ready I visualise letting go and it fluttering away in the breeze. It’s then out of my head and I distract myself with a task.
In the limited experience of my brain only, her intrusive thoughts are perfectly normal but disturbing to think of for the thinker. Admittedly I was an adult, but when my DTs were born I had so many intrusive thoughts of that nature, not about my doing it but the sick stuff people do to little ones. I’d had cbt and lived relatively ocd free for a couple of years beforehand so knew it was a flare up linked to hormones and had the tools to deal with it. It was still extremely distressing though!
It’s great that she’s talking about it though with you. My cbt therapist described ocd as being like a motorway. The rituals/behaviours are like the motorway in your brain, nice and easy to drive, smooth road etc, and the “normal” way is like an overgrown dirt track that’s a nightmare to get down. Cbt will teach me to get my brain to cut down the overgrown dirt track so that becomes my motorway, and the road I used previously would become a dirt track in time. Might help your DD to think of it, it made a lot of sense and brought comfort to me.
I know you didn’t ask about medication, but it maybe might be worth exploring. I didn’t take anything whilst having cbt and dealing with the crippling ocd as I was anti ads at the time. I only started taking them for pnd. With the benefit of hindsight I wish I had at the time, I put myself through hell and could’ve made it easier on myself as I learnt how to get my brain back to my new motorway.