iPhone with lower iOS version cannot be added as a friend to Game Center

My son has an iPhone 6 which is stuck at iOS 12.4.4 since it is no longer supported I guess. My iPhone is at iOS 13.3.1. When I go into my Settings/Game Center and try to add him as a friend, he receives a IM message asking if he will be my friend. When he clicks on it, a display pops up indicating he must upgrade to iOS 13.3 to accept the friend invite.


1) Is there anyway around this so I can add my son as a "Friend" in Game Center?


2) Most importantly, will I be able to "Invite" my son into a match using the GameCenterMatchMaker view controller when my game is completed?


If it matters, the "Deployment Info" for my game in XCode indicates a "Target = iOS 12.4" . I assume this means my game will be allowed to be downloaded by any iPhone having iOS 12.4 or greater ?