Sad situation made worse by relatives behaving poorly. You or you and other family members will need to consult with a probate attorney to have someone appointed as conservator of your grandparents' estate. You may request the appointment of a temporary conservator given the unfortunate circumstances, but someone will need to be empowered by the Probate Court of your local county superior court to manage your grandparents' affairs. You need to take these steps as soon as possible. Good luck.
You need to contact a probate attorney in your community to do the following things: (1) challenge your brother's efforts to be appointed conservator of your father and his estate; (2) have a temporary guardian of the estate appointed to secure your father's resources; (3) arrange to have you or possibly the public guardian appointed to oversee your father's care. You want to make certain that you hire an attorney who understands probate law and family dynamics.
No matter how mature, a 15 year old is still a minor and frankly quite young to have the responsibility of being a full-time caretaker of a medically and mentally disabled adult. I would encourage you to work with a social worker who specializes in elder care or a gerontologist to identify appropriate care resources for your elderly father. It might be possible to arrange for a level of in home care that allows the young person to provide some supervision to his grandfather but with an adult...
Review the attached link and contact a housing law attorney in your community. You should also use the county assessor's office to identify the current state of ownership of the property. You may also need to check to see if the property was part of a probate action.
Air conditioning for purposes of cooling a unit is an amenity rather than a legal requirement (i.e. a functioning heating unit). If the unit was advertised as having air conditioning then the lack of working air conditioning would be a breach of the rental agreement but I would not use this to justify non-payment of rent. Review the attached link.
You do not state whether you are a relative or close friend of the child or her parents. You also did not indicate whether you have a relationship with the child, i.e. former step parent. A legal guardianship in California can be a lengthy process and will require an investigation of you and the status of the child. There will also be an assessment of whether the child's parents approve of the placement and whether the parents will retain parental control over the child. Before you take...
As you are renting a room in a home rather than an apartment, your rights are somewhat more limited. While I do not fully understand what the LL is getting at, my sense is that it would be a good idea for you to consider whether you want to remain in this situation. If the LL is insisting, she needs to give you 30 days written notice of this change in the terms and conditions of your rental agreement.
The most effective way to get information from SSA about the issue you are raising is to either do a walk-in appointment or make a telephone appointment to meet in person with an SSA District Office staff person. You will need to have prove of your child's parentage and your relationship to the person who has died or become disabled and thus qualified the child for dependents' or survivors' benefits on that deceased or disabled person's SSA earnings record.
I recommend that you slow down a little. If you are evicting a tenant you should probably be going to Superior Court, limited Civil Division rather than Small Claims. Also as you are both owners of the property, you will both need to be named as plaintiffs and someone else will need to serve the unlawful detainer summons and complaint. I recommend that you review the attached link and contact a housing law attorney in your community.