It means that he has abided by certain mores for his whole life and by using the literal example of “pulling a thorn”, he’s saying, “there’s not one person who i haven’t helped, that’s what makes us brothers. When they need me i help them, and when i need them they help me.” It is interesting because he’s explaining that just because it’s not normal for you doesn’t mean it’s not my version of normal.
Balance your freedom and responsibility by managing your time. After figuring out your class (and/or work, internship, volunteering, etc) schedule, go through your calendar and set aside a specific time just for studying and homework.