If entering in the admin password each time doesn't work for you, you'll need to do some extra work, or run the script from a LanchAgent. That means the password has to be entered in each time the Applescript is run. If you look in that above thread, you'll see you will need to prefix your dscl commands with sudo though. Here is a related Q&A on a different forum that shows dscl embedded in an Applescript. Now that you know how to change the password using the command line, you need to embed that functionality into an AppleScript. Here's how to create a new user and here is how to change the password, which would be a command that looks like: The first thing you need to do is to use the dscl (Directory Service Command Line) tool. Ignore the part about how to do it if it's a newer M1 silicon machine.I can get you most of the way to the answer you need, but you'll have to do the actual implementation yourself. Here's a link with some more info and options and walkthrough basically. If you don't want anything on it you can simply reinstall the operating system from the recovery options window. Then you can save pics he may have had etc.

It'll ask which account you want to reset password on, select his account and make whatever password you wish and then it'll prompt you to restart, then use that password to login. Type 'resetpassword' as one word, without the quotes, and press Return. A new window will show up, waiting for you to enter a command. Then once the recovery options screen opens, With your Mac now in Recovery Mode, click on Utilities in the menu bar followed by Terminal. (Power on machine) and immediately hold down the command and R key for about 10 seconds or so.it'll boot up slow. If it's just a simple login password then yes and you can do that without data loss.

or it's a paperweight and nothing can be done unless you have original receipt and ID to match it and take it to apple. If it's an Apple ID passcode and firmware locked (file vault on) and it prompts you for that before it'll let you into recovery mode then no, you'll need that passcode or recovery key etc. (Power on machine) and immediately hold down the command and R key for about 10 seconds or so.it'll boot up slow

How to reset macbook admin password