Legal Question in Wills and Trusts in California

Re: Can I sue my brother for refusing to tell me about my fathers ashes

You probably could sue. If your brother was executor or a fiduciary, he is obligated to carry out your father's wishes if possible. His failure to do so may constitute and intentional or negligent infliction of emotional distress, as his refusal to provide information may be as well. I don't know how a jury would assess damages in such a case. I doubt an attorney would take the case on contingency for that reason and others. Either hire an attorney to pursue it for your on an hourly basis, or take him to small claims court.

Re: Can I sue my brother for refusing to tell me about my fathers ashes

Mr. Roth's answer is entirely correct. No one can guess if any trier of fact would give you anything for such a problem. Your first problem is going to be the statute of limitations; normally you must sue within one year of the injury.

Hire an attorney to write a sharp letter for you, but do not expect much of benefit to happen. Perhaps get one of you very young children to write a sad note to your brother about wanting to know where the ashes are.