Legal Question in Family Law in California

Not unless he hid the fact that the child was a step-child, and conducted his entire life as if he were the bio dad. Even then, it would not be up to him, but he could be held liable for support, and if so he would also acquire custody/visitation rights.

If the child had a significant bond to the step father then there is the possibility the court would allow contact between them if it is determined that it would be in the child's best interest to preserve that relationship.