I am a Civil Engineer with a Bachelors degree. In my state, you have to have the 4 year degree to get your Professional license. Without a license, you cannot assume any responsibility and sign any plans etc. Without tha ability, you do not make very much money.
I would suggest looking into the work he truly wants to do and see what they say about degrees. I know in my field, a masters or a Phd is only good for teaching or government research.
A two year degree does not do anything for an Engineering career in my field and does not qualify you to be one. A mechanical engineer will most certainly require a 4 year degree.
