Wonderful news about your boy! I think slippery elm, especially when combined with aloe, is about the best thing we can provide for these types of problems. It's a supplement/remedy in its natural form, and the body always loves those types of things best. I know Succeed and other ulcer products are very good, but, coming from an herbalist's point of view, I think the "real thing" is always a sure bet. I have two horses on slippery elm powder sprinkled over their grain twice a day forever, and it is a magic ingredient for them both (one ulcer prone, the other diarrhea prone).
I'm eager to hear what Madalyn says about maintenance, but I'd say "When in doubt . . . go the slippery elm route."
(I'm a poet and didn't even know it!)
P.S. I also recommend it to clients all the time, with great success.