Currently in online banking when setting up new savings/checking/CD accounts we only display names of existing joint owner relationships, not relationships that are only co-borrowers or beneficiaries. To be more specific, this person needs configured as “J” in the SECNAMES table (file), not a “B” (beneficiary) or “M” (miscellaneous owner).
The member can call the credit union, however, and a member of your staff can use CU*BASE to add this person as a beneficiary.