I am going through that now. Ultrasound showed a large stone which will not pass on its own. The surgeon said there could be more behind it.
I only found out because I have been having issues with digestion.
I have mine scheduled early July. I could have had it done this last week. But, I have travel plans and was uncertain of healing time.

I started a NO and very low-fat diet which is helping with the digestion and hoping it will be ok until the surgery.

Has he had an ultrasound? What are his issues?