Legal Question in Family Law in California

Children have not been considered property for at least a few hundred years. So you certainly cannot will them to someone. If the other parent is still alive you also cannot make a binding designation of a different person to be their guardian. You can, however, make a non-binding statement in your will. If the other parent is unfit, and the designated guardian is willing to take it on, that would give the designated guardian clear standing to seek guardianship over the objection of the other parent. No guarantees though.