I hunt out West and have a FP CS-24, Wildlife Tech, Minaska M-1 and the FP Patriot. The Patriot is a pretty nice call, I think it is an earlier version of the FP Prowler. It calls coyotes just fine.
Just starting out I'd really look at an inexpensive call with a remote. After you have some time under your belt you'll know what you need for the country you hunt. Coyotes have far better hearing than many give them credit for. I find loud highly over rated.
If your transitioning from deer to predators, what you can get away with hunting deer won't fly with coyotes. Your stand selection and how you manage yourself on the stand will be far more important than the sound and caller you use.
Good luck, what a plus to spend time in the field with your son
