Agree with comments so far .. learning on a manual is the way to go as it teaches much more vehicle control IMO .
Stay on the back roads for at least the 1st few weeks , be patient , try and take your son out every day , and for the first couple of weeks I'd suggest keeping the lessons to no more than 30 mins .
Ideally try and find a quiet road that has a T intersection (I was lucky, one near me) as it gets them used to intersections early.
As Wotto says, the 120 hours seems to take forever .
IF you feel nervous now, wait till you are in traffic LOL
Professional lessons are a must (at least 4 - 6) , so that your son learns stuff you, your wife forget to teach, or don't know .
Been through it twice with both daughters , glad its over now .
