I think you did a great service not only for the boys and their dads, but to horses. Every back yard horse owner want-to-be should have to have a class like that to let them see that being a horse owner is much more responsibility and work than most of them know. It is not all petting, feeding cookies, and perfect rides and behavior (not that yours weren’t) all the time. They need to know the cost of all those things you went over with them, too. There would probably be alot less uncared for, unwanted, unable to afford horses out there that you can’t give away in a horse sale. Also, the ones that went ahead and got one would know what all they needed to keep done for them instead of waiting till they were sick or down.
Teaching responsibility needs to happen when they are young. So many people KNOW what needs to be done but either "forget" or just don't care enough. Same thing with dogs. Animals rely on humans for most everything, so if you are going to have them their care needs to come first. First thing I do in the mornings is let my dogs out, then feed the horses, then feed the dogs, then I take care of me.