When creating a new email to my brother, his work address auto-completes when I type his name. I want is home address to be automatic.
Here’s the fix.
Open the Mail, Address Panel

From the Mail program, use the Window menu to open the Address Panel.
Select the desired Contact.

Find your brother in the Address Panel and click on his name. The default address will be highlighted. In the example above, the default is the work address.
Note: you can use the search box to narrow the list.
Select the default address.

In this case, click on the home address. It should be highlighted as shown.
You’re done! Close the Address Panel window