Mobile home park owner saying no to HVAC

[Adrienne Markes]

I've been trying to get an education on how much control park owners have over mobile home owners renting space in their park.  Here is the situation:

My 90 year old grandmother has owned a unit for 25+ years in a suburb of Los Angeles. About 15 years ago, my dad removed the swamp cooler and installed a HVAC unit on the roof of her unit (he is a HVAC contractor).  He was there doing some repair work the other day and the owner approached him and said the HVAC needs to be removed. That it didn't have the proper permit and even if he tried to get the permit, he (the park owner) would have to approve it and won't.

There are other people in the park who want to put in HVAC but he is saying no. So they are now asking why my grandma has it and they can't. Apparently, my grandma is "causing him problems because she has a/c".

The electric is metered by owner (my grandma pays her portion). She is on the same line with 7 other units. Electric hasn't been updated since 1960s. 

Who can we talk to to get help for my grandma to be able to keep her a/c? She can not continue to live there without a/c as temps get way too hot and for crying out loud, she's 90! 

Somebody help please!!