http://karlkimco.com/impact-filial-support-laws-state-california/
See http://codes.lp.findlaw.com/cacode/FAM/1/d9/4 I am not sure what "necessities" includes, but I would not be surprised that nursing home or medical cost might be included.
30 states out of 50 have similiar law. http://graphics8.nytimes.com/packages/pdf/health/NOA/30states.pdf