CoachV - There are winter showcases in the northeast, but they tend to be school/area specific. If your son is interested in some of the smaller northeastern schools, he could certainly begin to get some exposure and start to check out the competition. Schools like Fairfield University in CT, and Franklin Pierce in NH, run winter prospect showcases that are generally attended by other local colleges. If your son makes the trip to FPC, he might see coaches from Holy Cross, Fitchburg State, and such.
If he is talented enough to command the attention of the bigger D1's in the south and west, you might want to look into a PG showcase, but he'll definitely have to be prepared to compete against guys who play year round.
If he's a junior now, as my son is, he needs to identify the size school, type of community (big city/small town, etc), area of the country, etc that he's interested in and, if at all possible, narrow down potential majors. It doesn't make sense to spend time and money showcasing for schools he really isn't planning to attend. Narrowing the parameters will help with the budget, the schedule, and your stress level as you begin the recruiting journey. I learned all that from the great folks on this site and its already proved extremely helpful - thanks, old timers, for sharing.