I understand you're wanting to give your Mac away and you're needing help getting it ready for him to make it his own. I'd be happy to help.
The article below gives all the information you'd need to do before giving your Mac away:
What to do before you sell or give away your Mac - Apple Support
After doing steps 1-5, be sure to do this step to erase all saved information like passwords:
The best way to restore your Mac to factory settings is to erase your hard drive and reinstall macOS.
After macOS installation is complete, the Mac restarts to a Welcome screen and asks you to choose a country or region. If you want to leave the Mac in an out-of-box state, don't continue with the setup of your system. Instead, press Command-Q to shut down the Mac. When the new owner turns on the Mac, setup assistant will guide them through the setup process.
Optional step for MacBook Pro with Touch Bar
If you use a third-party utility to erase your MacBook Pro with Touch Bar — or if you use another method such as target disk mode — you might want to take this additional step to ensure that all information is cleared from the Secure Enclave in the Touch Bar. Start up from macOS Recovery by holding down Command-R on your keyboard immediately after pressing the power button to turn on your Mac, or immediately after your Mac begins to restart. When the macOS Utilities window appears, choose Utilities > Terminal in the menu bar. Type this command in Terminal:
Press Return, type yes when asked if you're sure, and then press Return again. Finally, choose Terminal > Quit Terminal.