How do I transfer a boarding pass from Apple Wallet to my wife or son?

1. Tap on the boarding pass, tap the Share icon .

and then select an option to share it.

click here ➜ Add, use, and share boarding passes, tickets, and other passes in Apple Wallet - Apple Support

Phil’s post is correct if the merchant permits transfers.

The boarding passes are controlled by the issuer, not Apple. Some issuers do not permit transfers. Some require the tickets be sent from your secure account on merchant website or mobile app to the other party (son or wife).