Kingsman, camps are held at colleges/universities and most of the time only the coaches for that particular school are there. They're usually one or two days and the kids that go are basically auditioning for that school's program. Sometimes D1 programs will hold camps that include other division coaches so kids who may not be d1 caliber aren't completely wasting their time. Even if a parent or player is extremely confident about the level they're shooting for it's a good idea (I think; others may differ) to go to camps that are at your dream level as well as camps that include coaches from other levels.
Showcases usually have more kids "auditioning" and many more coaches at the event. Some showcases have upwards of 70 different college coaches looking for players and the events are usually 2-3 days long.
For pitchers each type of event will have bullpens where the players' velocity is recorded and they may also pitch in game situations. Field players will work out in the outfield or at shortstop. Catchers will get a chance to catch of course, and pitchers may pitch in two consecutive days.
As you are researching what college camps/showcases you might take your grandson to you HAVE to get a video ready that shows him pitching AND has a radar gun visible in the video that records his velocity. In my opinion the video is a must. You need to send that video to the coaches of the programs your grandson imagines he might play for. Ask the coaches if they have a camp this summer and what showcases they are planning to recruit at. If they see a video of your grandson and they send him an email or text that they're interested then do what they ask for.
I'm not an expert on recruiting at the level you see your grandson at, so I can't help you with particular showcases that would allow him shine at the at level. One good alternative no matter what level a kid is at is Headfirst. The events you still have time to attend are in June, July and August, and the fall ones might be okay, too. Headfirst is either in California, Long Island, NY, or Florida. Google Headfirst baseball showcases and you'll find what you need.
I hope someone else will chime in with a little more information about stuff like WWBA. And I second Chasing 90s idea:
Just a thought. Find somebody to catch a bullpen and post up some video. There have been plenty on this forum that have been through the recruiting process that would give an honest assessment of whether or not he might could play at the next level.
This method would be the cheapest and most efficient way to get help about whether a specific college might be interested in your son. Chasing 90 means post the video HERE, to this site. You'll get an accurate assessment of your grandson's talents immediately. The video is also important because Coaches want to see stuff like that video and they want to know as much as possible about their recruits via personal emails before they go looking for them at whatever event they're at.
As they say, time is of the essence.