Answer:
Technically no
Explanation:
Technically no. The skin tone of the individual is caused by two factors, one is genetic and the other is environmental. The genetic factor will continue being there since the grandkids would be descendants of the grandmother. The environmental factor can change skin tone phenotype over the course of an individual's life. Although in this scenario, both locations have the same type of weather. Both Brazil and California are incredibly hot locations all year round.