My brother would belong to the Pre-operational from Piaget stages.
Basically, Piaget's four stages of intellectual (or cognitive) development are:
Sensorimotor. Birth through ages 18-24 months.
Preoperational. Toddlerhood (18-24 months) through early childhood (age 7)
Concrete operational. Ages 7 to 12
Formal operational. Adolescence through adulthood.
Where are the choices that I have to choose from? Anyway, I'll just provide a detailed answer to your question.