Wishing you patience. Most toddler sleep problems do eventually end, no matter what you do about them in the short run. It just takes awhile for sleep patterns to become regular. Sleep "training" is thought by some experts to be a way for parents to think they are accomplishing something worthwhile. Looking at the big picture, it actually seems true that even among babies who are "good sleepers," they will have periods or nights that they are not. And even among the worst sleepers, they will eventually settle into a fairly dependable sleep routine.
Kids' sleep patterns often change a few times during their first few years, for a host of reasons, many of which involve physical and emotional maturation. Here's a website that discusses just about everything to do with children's sleep issues: http://www.med.umich.edu/yourchild/topics/sleep.htm#sep. Based on what you've written, you might want to scroll down this page to two particular sections: "What do separation problems have to do with sleep?" and, "What if my child has problems settling in at night or resists going to sleep?"
I find your description of your current approach puzzling, because your son has little idea of why you have this (rather arbitrary) 30 minute "goal" he has to reach, or how long that is. He is only learning that if he stays loud and active long enough, you will eventually give him the contact and reassurance he's asking for.
Even if he "fake" cries to demonstrate his night waking to his grandma, that doesn't mean the distress he feels at night isn't real. I can tell a friend about a situation that distressed me deeply and be perfectly calm as I tell the story, but the distress I felt last week was entirely real. Your son does sound like an extremely clever little guy, though, and I'll bet you can learn quite a lot about his thought processes by asking him yes/no questions. And at two, there's probably quite a lot he'd like to be able to tell you.
I have a couple of suggestions you could offer him by way of compromise. You could try making a "deal" with him, that you'll sit by him quietly for awhile, if he lies quietly and tries to sleep. You could sing to him or tell him a story, stroke his hair or pat his back. For his whole life, I've done this on days when I visit my grandson (now 5), and the bonding is precious to us both. He relaxes happily and falls asleep fairly quickly most nights when I do this. If left to sleep by himself, it can occasionally take an hour or more – although he's past most toddler sleep problems, he still has evenings when he just can't sleep easily.
Another idea is to set up one of those rotating aquarium night-lights near his crib. They are rather soothing and hypnotic.
Some recent research strongly suggests that kids have a fair amount of variability in their emotional state from one night to the next, and while a pre-bedtime routine is usually a nice thing to establish, there will be nights when they need more comforting, or an earlier or later bedtime, for any number of reasons. So routines, ideally, should have some flexibility, allowing the parents to watch for particular needs being expressed on any given evening.
I sure hope you and your little guy arrive at an approach that meets both of your needs.
