Is this connected to that pseudoscientific "electric universe" silliness?
Not directly. The interesting thing about Sansbury’s thesis is that it does not arise from any sort of a search for grand unification theories or any sort of a back-of-the-book type solution to gravity. It arises from a very mundane study of reversible electrostatic fields being generated by currents, and the only possible explanation of the actual data is sub-electron particles. For the last hundred years or thereabouts of course, electrons have been thought of as indivisible, even as atoms were thought of prior to that time.