CA Prob Code Section 812

Except where otherwise provided by law, including, but not limited to, Section 813 and the statutory and decisional law of testamentary capacity, a person lacks the capacity to make a decision unless the person has the ability to communicate verbally, or by any other means, the decision, and to understand and appreciate, to the extent relevant, all of the following:

(a)

The rights, duties, and responsibilities created by, or affected by the decision.

(b)

The probable consequences for the decisionmaker and, where appropriate, the persons affected by the decision.

(c)

The significant risks, benefits, and reasonable alternatives involved in the decision.