Hello
According to your son's profile date of birth, is he a minor? If so, you cannot leave his user as the sole user on the computer. Even if you give him admin rights, due to his age, he will not have full admin access regardless. The computer will then become partially inaccessible due to the lack of full admin rights. Family safety will also stop working.
However, if your son is an adult according to his profile dob, then it is not a problem. Does he already have his own user separate from yours? If so, make sure his is set to admin type.. Then sign into his account, type netplwiz in the search on taskbar and press enter, then remove yours from there.
If he doesn't have his own user yet, and the current admin user is linked to your Microsoft account, then do this:
Go to Settings > Accounts > Your info
Click on Sign in with local user instead. follow the steps and finish the rest.
(If you don't see the "sign in with a local account instead option, click on "Stop signing into Microsoft apps automatically" first, then relaunch this page. )
Restart the computer (Do Not skip)
Go to Settings > Accounts > Your info
Click on Sign in with Microsoft account instead. follow the steps and finish the rest. sign into his Microsoft account here.
Restart the computer (Do Not skip)