Robyn:
If Eric is having spasms, as you suspect, then valerian root extract might help him. Valerian root is an antispasmodic herb. Eric could try taking one dropperful (about 30-40 drops) of the liquid extract 3x/day and see if that helps. I've taken much larger doses than that to stop coughing fits when sick, and it works like a charm. But I'd be careful about giving Eric too much at once; I just don't know how safe it would be for him to take large doses for his specific condition. 30-40 drops at a time should be very safe.
The valerian root might make Eric sleepy, so he shouldn't drive or operate heavy machinery while taking it.
If it seems to help a little and he has no adverse reaction to the herb with the standard dose (30-40 drops, 3x/day), you could slowly and incrementally increase the dose to see if it helps even more. The goal is to quiet any nerve irritation and stop the spasms, and then slowly wean himself from the valerian root. It's not something he should be taking in large amounts for a very long period of time (because it'll make him dopey). But a week or two shouldn't hurt; in fact, it very well might help him.
Just a suggestion...
Best wishes,
Tumbleweed