Does my bro (a minor) need notarized letter to travel to/from Mexico

I have a minor brother and I want to take him to Mexico. I'm over 18.

My father is in Mexico for Business. My mother (in USA) will be busy during the time period I plan to travel with my brother.

I plan to have some friends drive my brother and me or bus to Mexico. I know alot of times entering Mexico won't be a problem but entering into USA might as they look for proper documents.

My question is: Do I need a notarized letter

Yes. Plus you will need evidence of citizenship (birth certificate).

Yup..if you are over 18, you need your birth certificate and photo I.D. Under 18 needs birth certificate and letter of permission. See site below and read section on MINORS under "Entry Requirements tosee that the letter is Mexican law.

Yes. My son goes there every year with his dad. Your mother will have to write the letter stating that she is allowing you to take him and it's best to put the travel dates in the letter as well. You will need the proof at the border as well now. And I wouldn't suggest going through Juarez they have had a lot of killings there lately at the border.