Well... first off... I should say I obviously don't really know anything about this. So you have to take anything I say with a grain of salt, so to speak. That said... I would presume that if this person is employed by the Epilepsy Foundation, they're not a real social worker in the sense that they have any legal authority over you as might a county or state social worker in a situation where you were receiving government benefits. This is just someone who is employed by a not-for-profit organization to (supposedly) help people who have the condition the organization exists to support... in this case persons with epilepsy.

You don't have to allow anyone into your doctor appointment you don't want to have there. You also don't have to allow any discussion to occur, during your appointment, that you don't want to have happen. It's your appointment. But, of course, I know it can be difficult when you're shut in a little room with 2 or 3 professionals... all of whom assume they know what you need better than you do. It can be difficult to assert yourself under those circumstances.

The problem here, I would presume, is going to be this social worker doesn't have to give you a ride or help you out following your surgery if you need it. And if she's the only way you can get to your appointments, & the only person who can help you out following surgery, then you may be kind-of between a rock & a hard place as the saying goes. I suppose you could contact the Epilepsy Foundation & see if they have another worker you could be assigned to. But if not, & assuming you need the assistance this worker is providing, you may simply need to make the best of how things go during your upcoming appointment & beyond. It is true that these types of relationships can sometimes take a while to develop & smooth out. Perhaps, with time, you'll come to feel better about this worker. Hope things go well for you...