Welcome to the site! There are many previous posts that can be searched. There's also a recruiting timeline that lists some typical steps in the process.
In college baseball recruiting, tools matter not high school stats. Targeting academically oriented, four year colleges as a RHP with velo in the low to mid 80's as a 2018 puts your son squarely in the mix for academic D3 colleges IMHO.
The first step should be to create a vetted list of colleges where your son could potentially be admitted and potentially play baseball. A decent first barometer is to look at the 25%-75% window of ACT/SAT scores at potential colleges. If he's within that window, then this school is an academic possibility. For baseball, low to mid 80's should be in the ballpark at most academic D3's.
The list can be sliced and diced some more. Geographic location, majors and minors offered at the school, student body size, potential for merit scholarship in addition to need based financial aid, etc. etc.
This Summer 2017 is the primary recruiting season for a 2018 RHP targeting D3 academic schools. Once your son has his list (at this stage, maybe 25-35 colleges) he must begin to demonstrate interest to those colleges, both to his Admissions rep at each school and to the Head Baseball Coach (typically target the Head Coach at a D3 and the Recruiting Coordinator at a D1).
What does demonstrated interest look like? Complete the online Admissions and baseball forms. Email directly the Admissions rep and the Baseball Coach. Visit campus. Send an edited baseball recruiting video to each Head Coach. Meet the Admissions reps at college fairs and on his high school campus. Etc. Etc.
And showcase his skills this Summer by attending college showcases and camps where the coaches from the schools on his vetted list will be. He should communicate to those coaches in advance. Introduce himself when he's there. Follow up with the coaches afterwards.
There's a lot of things to do. Timing is now to make in happen!
We are all here to answer any questions. Good luck!!!