We have nothing that specifically addresses seizures, but it's true that just about anything that will help her relax at will (self-regulate is the jargon term) will be useful to her.
A few years back, there was an unsubstantiated myth going around that hypnosis and imagery might worsen the symptoms of epilepsy by adversely affecting brain wave activity. This has since been disproved by subsequent research, which showed that this may have been the case with non-epileptic "pseudo-seizures" but not with the real thing – and in fact, the reverse is true. As you’ve said, reducing stress is a big help.
I'm attaching some citations from studies that show (1) that a combination of aromatherapy and hypnosis was effective in helping reduce the symptoms of intractable or hard-to-treat epilepsy; and (2) that yoga can help as well. I was surprised to find that a recent review of the literature by Cochrane showed that acupuncture was not particularly effective.
She might want to try any of our stress reducing resources. Of mine, I’d suggest one of these: Stress Hardiness, General Wellness or Relieve Stress. I also recommend the beautiful work of hypnosis virtuoso David Illig, meditation teacher Bodhipaksa, Andy Weil’s breathwork, and much more. We have an awful lot of really good stuff for stress - and it mostly depends on what suits her best. I'd start with one of these and see how it goes first. Once you have a response, you can take it from there. And you can always call the staff or email for further direction on what we carry.
Rajesh B, Jayachandran D, Mohandas G, Radhakrishnan K. A pilot study of a yoga meditation protocol for patients with medically refractory epilepsy. J Altern Complement Med. 2006 May;12 (4): pages 367-71.