My brother says I should get treated because once in a while I get folliculitis? Is he right?

Depends.... ..On what is causing the folliculitis. You need to know the cause before you can know if it needs to be treated. A dermatologist can help you with that.
Folliculitis. Folliculitis occurs when hair follicles become infected, often with staphylococcus aureus or other bacteria. Certain variations of folliculitis are also known as hot tub folliculitis and barber's itch. Severe infections can cause permanent hair loss and scarring, and even mild folliculitis can be uncomfortable and embarrassing. Your brother is correct.