Multiple Airpods on same icloud account

My son and I both ave Airpods Pro and we both have the same icloud account setup on our phones. If I am using my Airpods and he turns his on, mine will disconnect. If I connect mine back, his disconnects.

Why?

And before you go off on a rant about you shouldn't share the same account, this is a kid and really don't need to have his own account in my opinion.