Thank you for your thoughtful comment. Your hypothesis is indeed profound, which I have not come across before.

Mechanisms of brainstem dysfunction are very complex, of which many I'm not familiar with. And I must admit that I'm not familiar with craniocervical instability and Ehlers-Danlos syndrome. I've heard that mast cell disorder is also understudied, and we are not quite sure of its role in autoimmune-related disorders such as collagen disorders. So, I'm afraid that I may not be much of a help.

But another commenter here (Philip George Hayward) has pointed things you may be interested in.