Family Setup and Contact Card

Family setup of an Apple Watch for my son through my iPhone. The watch is set up under his Apple ID. I have Contracts restricted to what I choose to add from my iPhone through the Watch app.

However in Contacts, it doesn't have anyone designated as the "me" contact - his personal contact card. I can't find a way to designate which contact card (i.e. my son's) is the "me" card.

This causes issues like in Maps I want him to just be able to ask Siri for directions "Home" but that doesn't work since it doesn't have an owner listed in Contacts. Any suggestions?