Do they mean craniosacral therapy?
This has roots in osteopathy but the specific approach I’m aware of does not involve ‘manipulation’; it’s a hands-on, light touch, whole person therapy. It is reputed to free-up restrictions. I’d look at The Craniosacral Society to find out more.
As with all therapies, it is recommended that the parents confirm that the practitioner is a member of an approved professional organisation etc. Also, if they want to pursue this, for them to discuss relevance and expectations before making any appointment.
Hope this helps.