This is not a Tax form: "The 5498 is for 2019 and shows funds as rollover contributions in box 2."

But you should confirm this is confirming exactly what the taxpayer told you happened. For instance, if that 5498 is a conversion, that would mean you do need to report the money Out of the original account and it's related computations, if that isn't what already got reported.

A 5498 is informational. Not for tax reporting.