I'm sorry to hear your news and wish you all the best. I have read, either here or perhaps another forum I stumbled on, of a lady with very limited leg strength, although I don't recall her condition or what happened - maybe that will jog someone else's memory and they can chip in.
In my very limited experience of multiple sclerosis, there can be a long period of time in which I think an e-bike could well be feasible, and would also provide some independence. From personal experience of long rehab from crashing my motorbike, I know that any psychological benefits shouldn't be downplayed - it was a huge boost to me when I got my bike modified and could get out and about again.
I'm afraid I don't know much about most e-bikes, but I do know that with my BionX I can use it either with a throttle (so no pedalling required at all), or as pedal assist, whereby my input is measured and mechanical assistance given. With this pedal assist mode, the BionX is easily adjusted (via codes entered into the controller on the handlebars) to vary both the amount of assistance given, and the point at which it is given. So, for example, it could be set to give maximum assistance at a minimum amount of force put through the pedal. I would have thought that something like this could well help you, and may be worth mentioning to the medicos as they may not be familiar with e-bikes.
One other thing I wonder is if, like Sheldon Brown, a trike would suit you better as it takes away the requirement to balance - again, one for the medicos, but I hope you don't mind my suggesting it.
Good luck!
Nick