I misread and didn't think doug was the owner. Cars cannot be parked on unimproved landscape. If the house is in bad shape it can't legally be rented out. There are also rules about subdiving property and multifamily residences, etc. From what you describe, I'm pretty sure there's something he can be written up on.
The website has a the codes so you can look and find what he is violating:
https://www.cityofsacramento.org/Community-Development/Code-Compliance
I don't know how Doug will deal with this or if you will get any blowback, proceed with caution.