bear in mind this - you can't do everything for them. They have to make some small decisions - like when to pull away from the kerb, and whether it's safe to move right for a turn. I nev er ask about medical conditions - if somebody wants to tell me that's fine, and if somebody asks a question I'll try and find an answer.
I'd second the TEC thing, but I'd also appoint the occasional wayfinder from time to time, making sure that they know who the TEC is. It avoids having to stop at every junction, and it brings you news from the back.