First, you should understand that the Turbotax license has never allowed you to share copies of the program with other family members. You are allowed to prepare more than one return, and in the past it has been technically possible to share copies of the program, but this was never actually allowed. For 2023, there is a new copy management system, that requires you to log into a Turbotax online account when you install the program, to verify you are the authorized user and to link your license code to your online user ID.
As a result, the workaround for your situation would be to send your son a copy of the software (I would use a dropbox-type service rather than mailing a CD), but then your son will also need your Turbotax Online username and password to actually install the program on his own computer. He will also need to pay for a copy of the California state module, since your "free" state module will be New York and that will be locked to your license code via the login function. And this procedure will still be a violation of the license agreement and is not officially supported or guaranteed to work.
Since your son likely has a simple return, he probably qualifies to e-file for free using the free version of Turbotax online. The thing to do that would be compliant with the license would be for your son to create his own TT account and file using the free version of TT Online. You could still do FaceTime or Zoom to walk him through the process. If he has a situation that requires upgrading to the paid version, you could then think about the best way to do that.
