Let's take inventory...
You know the kid loves to play and is a good player. You know he doesn't currently have D1 measurables and size and may not reach that going forward. You've learned the velo, projected velo and size are certainly parts of the equation with regard to college recruiting at the D1 level. You mentioned he has been told catching skills are high and it may be his ticket to a mid- D1... although there is a little bit of confusion to that point as you also say when he doesn't pitch, he plays corner IF with rare opportunities to catch (so, if he has such great potential as a C, why are coaches not putting him there when not pitching?). Also, you mentioned that he loves to pitch but didn't mention anything about a love for catching.
So, what are the takeaways?
With typical continued growth and development, he will likely be able to play somewhere in college but the right fit may very well end up being at a level other than D1. Be aware that maxing out at 79 doesn't fair well for him as a D1 catcher either. So, first, will that still fit with his goals (playing college ball at a sub-D1 level)? I know that can be a very difficult question to ask at this point as most HS sophs perception is that D1 baseball IS college baseball. If this does end up being the case, the recruiting timeline is later for those other levels, so he has time to develop overall without making immediate decisions about what position to focus on. He needs to also be aware that catching at the college level is particularly rigorous with a great deal of time catching bullpens for large pitching staffs, often sacrificing time with team hitting to do so. He REALLY needs to love it.
I don't think we can give you direct answers on this, but can give you additional perspective to frame your thought process with. RJM touches on a few very important points. How well he hits against top level pitching, of course, is also a huge part of the equation. And, probably most important, he has three seasons of HS and travel ball to enjoy. Be sure to allow for that to happen to the fullest for both of you. College ball may or may not happen for a wide variety of reasons. Yes, it is wise to allot some head space to planning ahead and asking these questions. But don't get too far ahead and forget to embrace the day.