Parent won't share insurance info- can we find out through CVS?

My partner is 25, with another 6 months until they turn 26.

They are on their mom's health insurance, but since their mom switched jobs, they don't know which insurance she has them on because, oddly, she won't tell them.

They know they are on a plan because they still get prescriptions covered at CVS, but don't know which insurer and can't find any of the insurance info.

Google says there should be a link called "Insurance Information" somewhere on the website, but we can't find it.

Is there a way, through CVS or otherwise, that we could check what insurance she is on?

For location context, we are in Rhode Island USA.

(crossposted on healthcare sub)