CBP should have, but did not, request the backup paperwork before approving the partner, but that is water under the bridge.

The partner should do exactly as requested if he wants his GE reconsidered. I'm not sure that "case closed" means in this context and it may be a real hassle locating 30-year old court records, but if you travel enough, the effort is worth it.

Try to track down the court records, obtain attested copies of the entire file (don't stint to avoid copying charges !) and submit exactly as requested.

Note that even if the paperwork is submitted, there is no guarantee of a result, but it seems worth the try.