In our area, there are gardens owned by a social service agency that then runs farmer’s markets for low-income folks, including seniors. I wonder if he could get involved with something like that, combining growing food and social service.
As others have said, and you realize, an 11 year old should not feel any pressure to think about college or career. Those career tests in middle school used to drive me crazy (actually my daughter was told she would be a clown or a conductor!). I don’t even think 18 year olds should have to think this way, but in this crazy world of high tuitions and loans, of course there are very real pressures to do so.
If this is what your 11 year old enjoys, great, but I would try to detach it from any discussion of future plans.
Does he grow anything at home?
The private school environment where he attends sounds potentially stressful- with 11 year olds apparently planning on becoming doctors and lawyers and Fortune 500 entrepreneurs. I would keep an eye on that because it creates unnatural, premature and competitive pressures on young people- and parents.
I hope he has a fun summer after an enjoyable year. Summer is quite a long way away unfortunately!