Are there grandparents' rights in the law of California?
My son died in May 08. Our grandson was born in July 08. They were not married, just engaged at the time. We went to court seeking scheduled visitations. The mediator stated right at the top of the meeting to both my wife, the baby's mother and me that there are no grandparent rights in California and that if she chose not to let us see our grandson, she was under no obligation to do so.
Unfortunately, it can be difficult for grandparents to obtain court-ordered visitation rights if the parent objects. It is a constitutional issue as parents have a "fundamental right" to make decisions regarding the custody and care of their children. The 14th Amendment grants parents this interest in "liberty." Thus, if a state law permitted its courts to grant visitation rights to nonparents, over the objection of the parents, then the law may be challenged as unconstitutionally infringing on the rights of the parents to care for their children in the way they see fit.
Of course, if the parent is unfit to be a parent, and it can be established to the court that it is not in the best interests of the child to be under the care of that parent, then this analysis changes considerably. But even then, the issue becomes one of custody more than visitation rights.
Your best (and least painful) bet is to reason with the surviving parent to an agreed-upon visitation schedule.