does a citizen of Mexico need a passport to go from the us to Mexico and back? He is legal to be in us but not a us citizen.
If you are US, Canadian or European citizen you can enter Mexico without the need of a visa.
yes
It is advisable to have a passport but a citizen of Mexico or the USA can do this with a drivers license.
No. A passport is required to travel internationally. However, there are some exceptions. For example, if you're an American citizen on a cruise that goes to Mexico, a passport is not required but a birth certificate and ID is. However, if you're an American citizen on a flight to Russia, then yes, a passport is required.
No, if such citizen keeps his/her passport at hand.
Yes, you do.
No not if your a United States citizen.
Yes, they do.
No. You need your US passport.
Yes, he does.
I am assuming you are a US citizen. The simple answer to your question is, no. International travel requires you to have a passport and in the case of some countries, a visa as well. Canada and, I believe Mexico, will accept a passport card