What they would do to the motorhome is irrelevant as an animal law question.
IF the conditions were as bad as you describe - a classic hoarding scenario - the animals would likely be taken. The health agent might also declare the motorhome might also be declared condemned as unfit for human habitation.
The foregoing is for general information purposes and does not establish an attorney-client relationship.
Report to Animal Control, as well as the City code enforcement office. Animal control is usually the County but the City usually have codes against this as well. The Animal Control Officer and City Code Enforcement can tell you what action they are likely to take.
We do not have an attorney-client relationship. I am not your lawyer. The statements I have made do not constitute legal advice. Any statements I have made are based upon the very limited facts you have presented, and under the premise that you will consult with a local attorney. This is not an attempt to solicit business. This disclaimer is in addition to any disclaimers that this website has made. I am only licensed in California.
You will want to continue to contact both animal control and the police. You can also contact either the city or county regarding the condition of the home. Further, you can contact rescue organizations in your area, particularly for cats -- they may get things moving more quickly. Be persistent.