Finding members of Learn for Life Family / Group accounts
In Destiny One admin page, the "Group Search" is under the "Student or Prospect Search".
Group Search looks in both the Family and Corporate Groups.
Usually the easiest search is Member First / Last name. If they know their Group Name/Number that works as well.

In search results, select appropriate group.

When in the Family/Group account page page, select “members” tab in the upper right.

Group Members page lists the members by name, you can select any member to see their account.

When in a user’s account, there is a link to associated groups (below communication settings)

Further Readings
Destiny One support tools (VPN required)
UNH Learn for Life / KSC Life Long Learning: Destiny One Enrollment Manager support tool (ETS Internal) - this is the tool where support staff can confirm identity, verify and provide email address, provide user name, and send or re-send user name or password to the user's preferred email address. Access must be requested ahead of time through the Accounts Management System (AMS) and this tool requires the VPN for access.
UNH Learn for Life / KSC Life Long Learning: Login Troubleshooting (ETS Internal)