At 13U, he'll want to play on the best team possible where he's receiving a satisfactory number of reps.
He'll jump to 14U this Fall, and tryouts for those teams will take place in the June/July timeframe. It's at this point where he'll want to consider a very good to excellent organization, again where he'll play a satisfactory number of reps.
At the 15U level, that's when you'll want to consider an elite organization, but only if he's forecasted to play. This is very important, as you can't get to the 16U level without succeeding at the 15U level! Ditto 16U to 17U.
While I agree with this 100% in terms of 14U, 15U, etc., for the OP poster's son, since he is a 2020, I think next year he is going to want to play 15U -- in other words, on a 2020 team. And I agree at that point you'd want to consider an elite organization. Otherwise, if her son does 14U next year, a lot of the competition in 14U will actually be in 8th grade, which I don't think would serve him well, long-term.