You can give specific users authorizations to access the whole GRUB menu, as well as to access specific entries in the GRUB menu. In either situation, you will need to add the user to the list of authenticated users using the bootadm set-menu adduser=username command. The password used to authenticate access to the GRUB menu is not the same password used by the OS when it is booted.
Once you have added the name to the list of authorized users, you can:
Add the user to the list of GRUB menu superusers, which will give the user access to all entries
Define a specific entry to which the user has access
To give individual users the ability to view or edit all entries in the GRUB, add the username to the list of GRUB menu superusers by using the bootadm set-menu add-superuser username command. Once the username and password are entered at the prompt in the GRUB menu, the user will be able to view, edit or boot all of the entries in the menu.
To give users authorizations to boot and edit specific entries in the GRUB menu, use the change-entry subcommand. to select which entries a user can access by either the index number or title. For example, the bootadm set-menu change-entry -i 3 add-auth=username command gives the named user the ability to edit the index entry 3 menu item.
Caution - If the default boot entry is locked, someone will have to enter the password before the system will boot. If it is important that the system can reboot without manual intervention, make sure that the default entry is not password locked.