I've heard mixed reviews about MMI. Our mechanic is the number one graduate in his class from MMI, and he is INCREDIBLE. After speaking with him, he said that he really didn't learn that much from the school because he was already very well mechanically inclined. Also, he is great at math, which is a MUST for a motorcycle mechanic (believe it or not).
One thing to ponder before taking the school is that breaking into this field is super hard. Our mechanic was lucky that he got swiped up by us. He gets to work on bikes all day long, build motors, do suspension, etc. Most mechanics when they graduate MMI become parts guys for years and years before they even get to change oil on bikes. If you can find a small specialty shop where you live that needs a mechanic, you'd be golden. But as far as getting a great mechanic job in the bike industry out of MMI, they are few and far between. Just do some research before you and your family decide to invest the time to make a move and the money it costs to get into the school.
I don't mean to sound so grim. Just want to give you the reality of the industry. It's not pretty sometimes.