Maybe he could alter the forwarder itself to 3 different Wiiflow folders? One for each of his kid then?
Wiiflow1 -> apps/Wiiflow folder1
Wiiflow2 -> apps/Wiiflow folder2
Wiiflow3 -> apps/Wiiflow folder3
And then from the Wii Menu Make 3 different Wiiflow icons that redirect to a different...