I'm not a doctor, but I doubt whether you should worry. There's some general information about varicoceles here:
https://www.urologyhealth.org/urology-a-z/v/varicoceles
And this is an excerpt from a report on someone who ruptured a varicocele after multiple severe sneezes:
A spontaneous rupture of a varicocele resulting in an acute scrotal hematoma is a rare phenomenon. Sudden increase in abdominal pressure, resulting to an increased venous pressure, can lead to a rupture of the varicocele.
As far as I'm aware, CPAP use does not increase abdominal pressure or venous pressure.
If you or your doctor continue to think it is possible there's some risk in CPAP use, I would recommend that you talk with the doctor about repairing the varicocele rather than using MAD for life or getting MMA surgery.