Any ideas on how to request increase of hours for IHSS (In-Home Supportive Services) through Medicaid/Medi-Cal?

I have been taking care of my mom for 15 years due to a consistent financial and psychological mistreatment history of my dad. My mom started to show some short term memory issue when she was about 67 years old. Her decline started right after she was laid off at the age of 65. During that period, my dad attempted to manipulate my mom into selling their home so he could go back home to retire. His condition is if she does not comply that he will leave in 2 months. Fast forward, it has been more than 10+ years now and he is still living with us. I went through immense hardship of shouldering the financial shortfalls for my mom for my dad obliged her to pay $500 (out of her $750 net social security pension) for his car. This resolved when the car was paid off through refinancing of their home. At present, I am doing much better with my full-time job income and some IHSS pay for taking care of my mom. The only challenge I am experiencing is that the IHSS case worker will not increase the benefit hours for my dad is technically still living with us. He does not have plans to leave for he cannot afford to rent nor become roommate due to the higher cost of living in our area. I hope there will be some feedback or guidance from the community based on experiences and resources they have received. The increase in IHSS caregiving hours will help me find a backup caregiver that could relieve me even for brief hours a month. At this point, I am starting to feel the impact of being the sole family caregiver.