My question involves landlord-tenant law in the State of: California

Hi im on here trying to get some information for my friend she is having a roommate issue so she asked me if i knew anything i told her i look it up for her. So she is living in a house owned by her grandfather she lived there 8 years. she pays rent to him monthly and she pays for the gas, water and electricity. Recently her cousin start staying there also. while there he has not help pay the water, are electric bill. She told he cousin last month the water will be cut off if he does not help pay. The water was cut off. So her cousin said he will go down there and pay for it. After doing so he locked her bathroom door so she cant use the bathroom. Also when he leaves the house he cuts the water off so she cant use it. She does not know what to do she gets her son on the weekends and they go to a hotel so they could have water to shower and so on. she told her grand father the land owner but he said he does not want to get involved. so shes stuck unless she finds a new place to move. She told the cops they said they send someone to talk to her cousin but when they arrive he's not home. Is there anything she can do?