I know this sort of sucks, but do you think he'd eat something like bologna or hot dogs cut into thin, noodle-y strips? Applegate Farms makes a grassfed, nitrate free beef hot dog, and I think they also make an organic bologna. Not the best option ,but still perhaps a way to get protein? Seems like lots the SID kids I've known will eat a more processed meat. My daughter has SID issues too, but meat is one thing, oddly, she's all about. She doesn't like most carbs, especially bread like things.
Anyway, would he eat spaghetti squash, which has pretty much the exact look and texture of noodles?