Your son’s application is much stronger than the average applicant but will be similar to many thousands of high quality applicants. There are a few things that might help to optimize his application.
Choose LoR writers who know your son well and can provide personal anecdotes to support their recommendation. There is a huge difference between “He is passionate in everything he does and has a special passion for speech” vs “His passion for speech has infected the entire club. In addition to leading by example, he is always willing to help his teammates both in improving their skills and instilling them a love for speech. The team has grown from 6 members when he was a freshmen to over 15 today, and X has been a big part of this growth along with the success that the team has enjoyed in district and state competitions.” It may be helpful to supply the LoR writers with a resume/list of accomplishments to make it easier for them to connect adjectives to facts.
Have a trusted friend (family friend, teacher (LoR writer ideally), relative, mentor) review the EC and essay parts of the app as a whole, not for editing purposes, but to get their view if the application is true to what is “special” about your son. The AO readers will be trying to piece together a narrative about each application from these pieces (as well as from the objective portions). Is the narrative consistent, does it ring true? Will the AO conclude, I know who this is and we need someone like that here.